In-Universe Game Clock

""SABRINA DIES AT DAWN!""

- One of the first messages you receive in the graphic adventure game Transylvania. They are NOT kidding.

A common trope in video games is the passage of time, including day and night cycles. Depending on the game, this can either be an attempt at realism or a way to introduce other features (including a night-based variant of the Underground Monkey). The result is one or more of the following:


 * 1) Time advances with the system-clock, or X times faster than the in-game clock--in the extreme case of some God Games, a game year may take only an hour to play.
 * 2) The time of day/week/month/year/whatever affects character statistics.
 * 3) Changes the types of monsters that spawn, or which NPCs can be encountered.
 * 4) Stores that sell items may be open, closed, or offer different items.

Of course, the time cycle seldom seems to affect the actual plot of the game (except in the case of a Timed Mission); events tend to happen at the appointed place no matter how long it takes for you to get there.

Contrast Take Your Time. NPC Scheduling is a subtrope.

Tied To System Clock

 * A more obscure Gameboy title, Itsumo Sakura-chan to Issho, also used a realtime clock, to keep track of card quests.
 * In the Animal Crossing series, the game clock is the real clock (as the Gamecube (and DS and Wii for the sequels), as with all current consoles, has a system clock built-in), so when they say "come back tomorrow", they mean tomorrow. The original game has special calendar events programmed in for a few more years, and it's been out for a while. Of course, games like this make it possible to "time travel" by changing the system clock.
 * The games would prefer that you change the clock in-game.
 * The games can go take a flying leap, because changing the clock in-game causes bugs that changing the system clock doesn't. (You'll still be punished for blatant time-traveling regardless of which method you use.)
 * The real original title, Doubutsu no Mori "Animal Forest", for the N64, couldn't use a system clock, since the N64 didn't have one. While one would expect a clock to be built into the cartridge, you actually had to enter the time whenever you started the game. Sure made it easy to catch up if you missed a day. Or a week. Or a year.
 * Another exception: in Operation Flashpoint: Cold War Crisis - a tactical shooter - time passes in real-time, and changes in time of day are gradual and usually only discernible either early or late in the day. Sunrise and sunset times even vary depending on the month.
 * The tides and visible constellations also vary. One mission even requires you to navigate by the stars.
 * City of Heroes has a constant day-night cycle that seems to last about an hour or so, and talking to certain passers-by on the street will get you the "local time" according to that cycle. There are a few villains and recurring events that will only appear outside at night.
 * In Sega Dreamcast racing game Metropolis Street Racer, the system time is used to produce a realistic time of day in the three cities London, San Francisco and Tokyo. Some bonuses are only available at certain times of the day.
 * In the World of Warcraft, the day-night cycle occurs in real time. There is, however, next to no effect on gameplay; monster spawns remain constant, visibility remains the same, and NPC shopkeepers remain open for business at all hours. The only change is that certain fish can only be caught at certain times, but since those fish have no special abilities and the recipes that can be cooked with them aren't particularly useful, this is trivial.
 * Pyrewood Village in the Silverpine Forrest is inhabited by humans cursed to change into worgen at night. The villagers are friendly to Alliance during the day and hostile at night, and always hostile to the Horde.
 * Also, recently-introduced daily quests can be repeated by the player, but only once per day. The reset time for these quests is a few hours after midnight server time (1AM PST, 2AM GMT). In-game, many daily quest-givers seem aware of the daily nature of quests, and inform you to return the next day to repeat the quest.
 * The game also rewards players for not playing by granting them a period of faster Experience accrual while they're resting (logged out, at an inn, or in a major city). The longer the character is logged out, the more bonus EXP they earn (within limits, of course).
 * The amusingly named flight sim Corncob 3D has you create an avatar to serve in the game's air force, and as you complete missions you'll get medals and promotions. Do something stupid like bomb a friendly base instead of an enemy, and you'll get thrown in the brig for a few days to a week... and they really mean it. Come back in a week and you can play the game again!
 * Since Nethack is a turn-based game, time mostly doesn't matter. But when it does (Gremlins, for example, are only dangerous at night), it uses real-world time.
 * Also special in that it keeps track of not just hours of day but also days of the month (kinda): It uses full and new moon days for certain effects.
 * Second Life has a somewhat long day/night cycle that also affects the client program's login screen. It can be modified by a surprisingly in-depth editor, but, of course, only changing the look of that particular player's client.
 * Seaman for the Sega Dreamcast ran on the console's internal time to make keeping your Seaman alive something of a daily thing. For instance, if you feed Seaman once then go away for a week, Leonard Nimoy will tell you that your fish have died.
 * Of course you can change the Sega clock to speed up the game to the point where you can play the whole game in just a few hours. Nimoy lampshades this by telling you that he's noticed that you get on a lot at this time.
 * The Creatures games have an internal day/night cycle and seasons. In most of the games, this only affects a few plants and such and makes everyone a bit sleeper at night, but the kids' versions, Creatures Adventures/Playground, have the entire scenery change. Also, there's in-game time, which (I think) is supposed to match Real Life time, but depending on your computer it can be much faster or slower because it's based on processing speed. This is used to describe the age of the creatures (who usually have a lifespan of around 4 in-game hours).
 * The DS Dating Sim Love Plus ignores this until a confession of love occurs (and the credits roll), then it gives you the options to play in "Skip Mode" (which isn't tied to any clock whatsoever) or "Real-Time Mode" (which is tied to a 1:1 clock, initialized to your DS's time). Additionally, some features, such as buying a present for your lover, are only available in Real-Time Mode. thankfully, the game will let you go back and pick up (most) missed events in Real-Time, provided you had them scheduled, with dates being among the sole exceptions.
 * Very odd example in the second and third Ratchet and Clank games; they have a 'level' called the Insomniac Museum in both, which in both is simply a large museum of (sometimes interactive) objects and concepts that didn't make the final cut. There are two ways of getting to it: beat the game 100% and then feel free to select it from the menu at any time, or find the one teleporter that will take you there. What does this have to do with this trope, you ask? The teleporter can only be used between 3:00 AM and 4:00 AM, according to the system clock. Made all the stranger by the fact that the games never so much as hint at this contingency.
 * It's an Insomniac Museum, get it?
 * The web game Farmville runs in realtime (except that game days are 23 hours, not 24, for convenience). If you leave your farm alone for too long, all your crops will have withered. Thus, the game rewards good planning.
 * Just about every Facebook game either has an Energy system (that replenishes in real time) or, like Farmville, have a "do this action, then come back later to reap the rewards" system.
 * Oracle of Tao has not only hours and days, but weeks and months, and basically a working calendar. It even has seasons (where the grass color changes (to look like snow in winter) and weather pattern becomes drier in summer or more snow in winter). They don't have actual years passing though, instead the same year loops infinitely.
 * And yes, they do have stores and such that close at night.
 * Telefang has an internal clock, although this doesn't serve much purpose other than graphic effects (for daytime and nighttime) and receiving messages from other characters while the game is turned off. The clock was dropped in Telefang 2.
 * The World Ends With You uses the DS system clock to determine how much Shutdown PP you receive. Which also means that you can modify the DS clock for truckloads of Shutdown PP.
 * Each character can also only digest so much food per real time day meaning you can't feed them again until tomorrow. Like with Shutdown PP this can be avoided by tweaking the date on the system clock.
 * Paper Mario the Thousand Year Door has the Happy Lucky Lottery which can be played once a day, according to the Gamecube's system clock.

Internal Game Clock

 * Pokémon Gold and Silver started the series' tradition of built-in clocks that segregate the day into three time periods -- morning, evening, and night -- as well as keeping track of a seven-day week. In order to complete certain events or capture certain Pokémon, you must play the game during those time periods. The day-night system was lessened in importance in Pokémon Ruby and Sapphire and dropped for FireRed and LeafGreen (themselves merely being remakes of Red and Blue anyway), but made a return in Pokémon Diamond and Pearl.
 * The DS remake of Gold and Silver sees the time/day function return to true importance, as all of the date- and time-specific events from the original versions return with gusto.
 * Pokémon Black and White expand on this by adding seasons. Every real-life month, the in-game season changes (January, May, and September are spring, February, June, and October are summer, March, July, and November are fall, and April, August, and December are winter). Like with the day-night system, different Pokémon appear during different seasons or appear at different rates (for example, some ice Pokémon only appear during the winter, and others appear more frequently then). Also, just like in real life, the days are shorter during the winter and longer during the summertime.
 * Project Zomboid: Features one. Night time is harder to see, which makes it easier for zombies to attack. 6 hours of real time equals about a month in game time.
 * Activision's Robot Tank, a 1983 title for the Atari 2600, may be the earliest video game to feature a day-night cycle.
 * In Chibi Robo, the day is initially five minutes long, but can be extended by buying special items. And you can change it back, if you'd like. Essentially, the game allows you to choose how long your days are.
 * In the otherwise gritty and realistic world of the Grand Theft Auto series, a day passes for every twenty-four minutes of play time. As an extension, some missions can only be started at a certain time of the day.
 * In Grand Theft Auto IV they halved the in-game clock's speed, meaning that one in-game day passes for every forty-eight real-time minutes.
 * In IV, your friends and girlfriends have individual sleep patterns - and aren't too happy if your phone call wakes them up.
 * And throughout the series, saving your game causes a few hours to pass as your character gets some sleep.
 * In IV, spraying your car will make 3 in-game hours to pass.
 * Another Rockstar game, Bully, also uses a in-game clock, also with a day lasting twenty-four minutes.
 * On this game, though, the clock plays a bigger role, as your character will pass out after 2 a.m., and you have to attend classes or the prefects/police will try to stop you and take you to it. There is also a curfew after 11 p.m., and they will take you back to your dorm if they catch you.
 * And some missions slows down or stop the clock completely.
 * In The Legend of Zelda, at least the 3-D entries in the series, there is a compressed day/night cycle (which only operates in certain areas, others are locked at the time of day it was when you entered them.) Of course, in all the titles with a time component, save one, there's a method to screw with it via music.
 * The 'save one' would be Twilight Princess, which received a number of complaints because some people who were used to the first few 3-D entries were too impatient to wait a full 10 minutes for 12 hours to pass.
 * Transporting to the penultimate dungeon automatically changes the time to day, but there is no such shortcut for night. This really bothers players when hunting for Poes, which only appear at night.
 * it does bring you back late in the day, so it's still a quicker way to bring on nighttime than just waiting it out.
 * An interesting note is that Wind Waker makes use of this at one point. You are told by that her gang won't leave to follow you until morning. Most (at least, most first-time) players take that as a cue to rush back to your boat and sail right toward . However, as the player will no doubt notice, and the King of Red Lions will point out, something strange has happened causing the world to be in constant night for this segment of the game.
 * The day/night cycle is of highest importance in Majoras Mask. Basically every single sidequest in the game (as well many parts of the main quest) all depend heavily on the game's internal clock. And if the internal clock counts down to 0, it's game over.
 * Skyward Sword has day and night, with NPC schedules and monster appearances changing along with it. However, the change is triggered not by the actual passage of time, but by Link going to bed.
 * In the 1983 8-bit classic Knight Lore, the main character turns into a werewolf at dusk then back into a human at dawn. The whole 24-hour cycle can take, in real time, anything from mere seconds on an emulator running at warp speed to at least a minute on the original machine when a lot of moving blocks/sprites are present. Several of the enemies react differently when you're in wolf form (most notably, it's impossible to enter the wizard's room as a wolf).
 * In all three The Sims games, at the slowest (default) speed, time compression is 60:1; that is, one in-game minute takes about one real-time second. Since animations must still be carried out in a realistic speed, this means that characters take half an hour to go to the toilet, or an hour to have breakfast.
 * Okami cycles from day to night, with many quests that can only be completed during one or the other. You start the game with the ability to turn night to day, and eventually learn to turn day into night as well.
 * The Elder Scrolls IV: Oblivion has 1 minute in-game equal to 2 real-world seconds. As time passes, it gets dark, eventually shops close, and so on.
 * There are cheat codes built into the game, interestingly, that allow you to change this ratio. Ever wanted to recreate the scene in The Time Machine (or, for you younger players, Futurama) where the days and nights move so swiftly that everything becomes a blur? Set the radio to Decade-Per-Real-World-Seconds.
 * All the main The Elder Scrolls games since at least Daggerfall, and especially Daggerfall where most quests were timed to some extent, have been heavily reliant on in-universe calendars and clocks to determine night/day cycles.
 * The Baldurs Gate series uses six seconds of real time to equal one minute (which, conveniently enough, is the length of a combat round in Advanced Dungeons and Dragons), and extrapolates outward from there. Many locations and people would remain available 24/7, but there were definite exceptions; also, certain Random Encounters were exclusive to day or night.
 * In contrast to this, many scripted events in the second game would appear a specific amount of real playtime after the previous in the sequence. One could cheat the system a little by pausing the game and leaving it alone for an hour, then unpausing it to see if the next event had triggered.
 * Neverwinter Nights, the Spiritual Successor to Baldurs Gate, had two minutes of real time equal one hour of game time.
 * Sierra's Quest for Glory series would close stores, bar the city gates (whether you were inside or out), and put most civilians to bed past certain hours. This was also the only time thief characters could get in their looting. Furthermore, the series also kept track of the number of days elapsed and would advance the plot accordingly; beating the game was usually not possible until key events occurred several days in. An unnoticed time-keeping bug in Quest for Glory III unintentionally forced the player to be in a certain city on a certain day to take part in an important plot point; if the player missed the event, it would not reoccur -- and the game would not be able to proceed.
 * Quest for Glory II is one big time-based mission.
 * King's Quest III doesn't have a day/night cycle, but it does have a clock that starts at 00:00:00 in the status bar, and some game events are tied to it. For example, figuring out when the evil wizard will and won't be home will let you avoid being killed by being in the wrong place at the wrong time.
 * The day/night cycle in King's Quest IV is usually triggered by events, but if you wait a veeeeery long time night will eventually fall on its own. Sadly, if you didn't do the event that triggers nightfall you'll end up being killed by zombies anyway.
 * In the Myst game End of Ages, the solar system which the world of Laki'ahn belongs to is structured such that there is a solar eclipse every five minutes.
 * Dark Cloud 2 also runs an accelerated time-pace. Shops remain open at all times, but various characters can be found in different places at different times. They never actually sleep, though. The time of day is mostly important for catching specific photographs, such as the full moon or the sunrise. There's also the 'Lamb Sword', which transforms into the 'Wolf Sword' at night, with a MAJOR increase in attack power.
 * Capcom Zombie Apocalypse game Dead Rising covers 72 in-game hours in 6 real-time hours. The Infinite mode grants the Infinity Plus One Sword if you survive 10 real-time hours without dying (no saves, either), and an additional Bragging Rights Reward for surviving 14 real-time hours with no saves.
 * Radiata Stories has a 24-hour day/night system where the plot advances by doing certain activities at certain times. This unfortunately leads to a lot of instances of the Lost Forever.
 * Harvest Moon: Magical Melody has roughly 120:1 time compression, where 10 minutes of game time pass in 5 seconds.
 * Most Harvest Moon games have super compressed days and nights, although the player is not encouraged to play too far into the evening (Harvest Moon being a farming game, after all). The short days, which usually pass in much less than half an hour, can be extremely annoying when the player has work to do, and one often has to make decisions on what to do that day, because there simply isn't time to do everything after the mandatory crop watering and animal feeding.
 * Though, in most games, time suddenly and inexplicably stops whenever you enter a building, making loitering in shops and talking to people take literally no time at all. A Wonderful Life, however, never stops the clock unless you pause, and Welcome To The Wind Bazaar never stops time ever, not even while looking through menus.
 * In the Pikmin games, each day lasts 13 minutes. This does not include time spent in dungeons, which apparently has something to do with powerful magnetic fields.
 * The interesting adventure game KGB had a nearly 1:1 timeflow. Days were quite action-packed (you should be able to finish the game within a weeks worth of game time) but travelling and the "wait" option sped things along.
 * Agent USA, an Atari game made in 1984, has a night and day cycle that was quite advanced for its time. Time moved at the speed of real life, but sped up considerably (as in, an hour per second) while riding a train from one location to another. For every two hours in the game, there's a different color for the sky, buildings, and the windows in the buildings may be lit up or not, providing twelve distinct times of day.
 * Star Fox Adventures has a shortened day and night. Characters that are unimportant to the advancement of the game sleep at night, but most important characters never do, making day and night almost as irrelevant as whether it rains or not. Notable exceptions: Tricky sleeps, occasionally requiring you to awaken him if you want him to use a skill; and a SnowHorn in SnowHorn Wastes gives you an item necessary to leave that part of the world if you feed him, and makes it possible to leave that area with a little effort if you feed him again. However, you can't feed him when he's asleep. Oh, and the GrubTub Fungus, a mushroom necessary to feed Tricky for him to perform a couple of his skills, hops around during the day, and sleeps in place at night. The latter condition is much easier to collect them in.
 * The unreleased Star Fox 2, a combination of a real-time strategy game and 3D space shooter, has time continuously passing throughout the game, whether you're on the map or in battle. However, time runs at a slower speed during battle.
 * The Witcher has a full day/night cycle and a clock, where half an hour of game time is about five minutes of real time. Not only are some missions only possible during day or night, but for some you have to be in the right place at exactly the right hour of the day.
 * Battle for Wesnoth gives the day/night cycle strategic relevance by making lawful units more effective during daytime and vice versa for chaotic units.
 * Castlevania II: Simon's Quest: What a horrible night to have a curse. (The Angry Video Game Nerd considered the unskippable message a Scrappy Mechanic.)
 * Monsters are tougher at night, but the music is so much cooler. Dilemma...
 * Heart pickups are also doubled at night, but the towns are all locked up and full of zombies, which don't give you hearts. The dilemma continues...
 * Later Castlevania games like Castlevania Symphony of the Night and Castlevania 64 also have day/night cycles.
 * Sierra's edutainment game Gold Rush has two timed events, both of which completely fail to work on any computer faster than 25mhz. There was also a segment with day cycles (no night cycles, it just transitions to the next day without warning) that tend to get you killed by putting you into a bad situation, because you were standing at the wrong place WHEN DAWN CAME WITHOUT WARNING.
 * The X-COM game series allows the player to control how fast the game will be - from 5 seconds to one day for each real life second. Any events that happen will automatically freeze the clock. This is very, very important, as sending rookie troopers into a night mission is essentially the same as shooting them in the head, only more involved.
 * Fallout ran real-time on area maps, but with time compression while traveling on the overland map. Fallout 3 and New Vegas used the same time compression scheme as Oblivion, having been built on the same Game Engine.
 * Fallout 3 even has changing phase of the moon.
 * Most but not all shopkeepers are affected by daytime. In Fallout 3, other activities (most notably sleep) are also affected.
 * There are perks -- passive abilities that can be selected upon leveling up, provided certain conditions are met -- which give bonuses during day (e.g., health regeneration and additional strength) or night (e.g., additional perception and intelligence). Shopkeepers, however, can be interacted with all night long, provided they stay in their shops all night instead of going home and sleeping (which sometimes happens in New Vegas).
 * Rogue Squadron II, of all things, uses a day/night system on a few of its levels. The initial training mission changes depending on what (real-world) time of day you play it; a later mission has you attack a base's early-warning sensors head-on in a bomber when played during the day, or sneak in with a speeder when played at night.
 * Far Cry 2 also has a fairly long day/night cycle. One minute of real time is equal to five minutes in-game. It gets odd to think, after blowing up a few convoys, assassinating a bunch of guys, taking over a number of safe houses by force, helping out the underground a couple of times, meeting and helping out a few new friends, all while conducting complex operations for one militant faction only to switch sides and work for their enemies across town, that you've still been in the country less than a week.
 * Dragon Quest VIII has a day-night cycle of about a half-hour. However, the player can circumvent this with most inns: going to an inn in the middle of the night has you wake up at dawn, and going to an inn during daylight gives you the option of sleeping until the next morning or only until evening.
 * Earlier Dragon Quest games had the same cycle, though the inn would always take you to morning. There were also spells and items that would change it from day to night or back.
 * The in-universe clock got very strange in Dragon Quest V, in which, according to the in-universe day-night cycle, your wife gives birth to your twin children maybe three weeks after the first opportunity for conception.
 * Vandal Hearts 2 has time pass as you travel from checkpoint to checkpoint, and some maps will have different enemies and features during night-time. Also, some events can only take place at specific times.
 * Sim City. Even at the slowest speed the game proceeds at a rate of many days every second. At the fastest speed, a year goes by in only a few seconds. The game goes slower during a disaster like a fire, but the whole incident still goes by in 5-15 minutes.
 * Sim City 4 has a day-night cycle as well, but of course it doesn't proceed at the same scale as the calendar; each year contains only a few.
 * Hostile Waters has a day/night cycle that doesn't affect gameplay beyond giving you an excuse to use the night vision button. If you know one exists at all.
 * The Phillon Planet in Ace Online experiences a day-night cycle, complete with a moving sun and moon. This only affects the spawning rates of mobs, as some are nocturnal.
 * In Breath of Fire, the first two games has this element in play. The first game uses it as a story element twice (the third town can only be accessed during the night, as is a password needed to open Tunlan's safe). Breath of Fire II has specific places not accessible at night, like the church and circus.
 * My Sims time is sped up, though you can still Take Your Time to complete any task. For the most part, whether it's day or night only affects who's awake, though you can wake anybody up without consequence. (If you're like me, though, you feel bad about it. Unless it's a situation where I just gave the Sim a BED.)
 * My Sims Kingdom is an odd case: each island's day/night cycle is suspended in daytime (yes, it's day in Rocket Reef and Spookane when you arrive) until you complete that island's story. There's another round of improvements you can make on each island, but time passes, anyway.
 * Burnout Paradise uses a clock system that is normally compressed. However, there is a menu option to lock it to day, lock it to night, or sync it to real-world time. This has the added use of giving the player the choice of when he wants to do specific day/night events. The player can also alter the time it takes for 24 in-game hours to pass, ranging from 24 minutes to 2 hours.
 * Oddly enough, an early version of Sonic the Hedgehog 2006 had a day/night cycle. There was a video or screenshots where this was shown off; as the sun travels through the sky, the real-time shadows under Sonic's feet, and the ones produced by the random crates and the tree, are quite breath-taking. Why they didn't put this in the retail version when they actually had the code made and in the game back then and in good quality is anyone's guess.
 * An even better question is why they spent so much time creating that cycle instead of working on the game's many other problems (such as the terrible controls, the awkwardly implemented physics, the never ending loading times...)
 * In the first two Way of the Samurai games, time does pass whether you're following the plot or not. However, time passes only while traveling, so it's possible to Take Your Time if you don't leave the current area you're in. In the second game, you have an entire month to spend exploring Amahara, and can still spend the whole time collecting swords and staying out of the plot. However, the third game appears to follow this trope more traditionally, letting you Take Your Time a bit more.
 * Fable deserves an honorary mention as time does flow by, but only for the Player character, resulting in situations where you at the age of 54 has to go save your older sister who looks suspiciously 20-something, and you can go save your mother who is now younger than you.
 * The fact that, at least for the Player character, this is averted in Fable II should give an idea of just how annoying it was to have the Player age years seemingly in days.
 * Seiken Densetsu 3 - Kevin, being a werewolf, transforms and becomes much stronger at night; magic may also vary in effectiveness depending on the day of the week, but it's not too obvious; most stores are closed at night, and the inn offers free stays on Holy Mana Day.
 * Rogue Leader has alternate day/night versions of certain missions, depending on the real-world time.
 * In Interplay's Lord of the Rings, "you cannot enter the town of Bree at night." That is, unless you have someone use the sneak command and walk real close to a wall near the bottom of the fortress. Also, the blacksmith will not help you with anything while it's dark, even though piecing together your sword and equipping you with armor could save the lives of everyone in Middle Earth.
 * Shantae has a day-and-night cycle in effect while you're wandering around the field. (It freezes in towns.) Monsters are not only more difficult at night (they have much more HP), but in towns, different NPCs will be out, some shops will close, and a certain town will only appear on the map if it's nighttime. Oh, and one area has zombies.
 * The day/night cycle in Beyond Good and Evil is mostly atmospheric--only a few NPCs have schedules, and none of the shops close--but a few animals you need for the First Person Snapshooter/Collection Sidequest only appear at night/day.
 * Platformer Vexx has a day-and-night cycle in the levels, which advances at a slow rate, but can be controlled via magic sundials in some parts of the levels. Monsters change appearance and have more health at night, and certain levels have sub-levels that can only be accessed at specific times of day.
 * Leads to awesome Fridge Logic in Roller Coaster Tycoon when you realize that your park guests have been standing in line for months without eating, sleeping or going to the bathroom.
 * Clearly you've never been to Disney World.
 * Also worth noting is the game's calendar, which starts at March and ends at October, as per a theme park year. This only serves to compound the Fridge Logic, as you realize that between October of one year and March the next, literally nothing happens. R&D completely shuts down, Advertising takes a break, and those guests are still standing in line.
 * Brave Fencer Musashi uses an in-game clock that marks off an hour a minute (except when paused, sleeping, or fighting bosses) and a seven-day calendar that results in shops being closed one day of the week apiece and.
 * In Hearts of Iron (1,2 and 3) every in game hour is a turn and you can control the speed at which time passes (and also pause it completely). Fighting at night comes with hefty penalties to both the attacker and defender and night bombings and air battles are also much less effective. Also certain technologies offer bonuses that improve effectiveness at night (such as night vision gear, aircraft radar and special night training).
 * In the first Soul Series game, Soul Edge, the sky changes from dawn to dusk over the course of about 4 minutes. This has no bearing on the gameplay, and is simply used to show off the game engine (and to look cool.)
 * Mount and Blade has one, though it takes only a short time for a day to go by.
 * In The Godfather: The Game, time passes faster "normally", though I'm not too sure by how much faster, though there are still Timed Missions that act as though in real-time. Plus the game gives you "two days" to strike first in ending a Mob War, but the onscreen timer shows 48 minutes. Hmph.
 * Dwarf Fortress keeps track of how long your dwarfs have been at the fortress, and things like weather, available crops, and arrival of traders are tied to the season.
 * The Lord of the Rings Online has an internal clock that makes an entire day last a little over 3 hours. While no specific in-game time is shown, an icon surrounding the mini-map will either show a sun or a moon, indicating whether it's day or night, and the tooltip will display the actual time period (dawn, morning, noon, afternoon etc.). In addition, the sun/moon cycle in the game is portrayed accurately throughout that 3+ hour day.
 * In Resonance of Fate, time passes at a set rate while on the world map, or skips ahead if you rest... but it stops passing once you enter a location and also stalls for plot-related reasons. The bizarreness of the fact that it can potentially be day for more than 24 hours if you're dawdling, then suddenly turn to night in a few minutes and refuse to change until you finish whatever plot points require it to be night is actually Justified Trope -- the game is After the End, and the many disasters include some form of alteration to the Earth's axial rotation that makes the day/night cycle unpredictable. The physics of how this could work without the speed of rotation changing causing all sorts of problems is best not thought about too deeply, though.
 * Earth 2150.
 * Shenmue among other innovations was one of the first to have an in game clock and the game ended if it took too long in game time to beat it.
 * The Ultima series features the Avatar's pocket watch which first appears in Ultima V and is subsequently returned to the Avatar every subsequent time he comes to Britannia (having left it after the previous adventure). The watch tells in-game time and is helpful for keeping track of NPC schedules but never serves a plot significant purpose.
 * A full day cycle in Minecraft lasts 20 minutes (equal to 72:1 time compression). In single player, you can skip the night by sleeping in a bed.
 * The Etrian Odyssey series has a day-night cycle, as well as an in-game calendar (for instance, the guild always starts its adventures on Emperor 1). Time advances as you explore the Labyrinth, and when sleeping at the inn, you can choose to be awakened in the morning or evening. Depending on the time of day, different monsters may appear in the Labyrinth, or FOEs may behave differently.
 * In some areas, however, this behaves oddly... For instance, in the third game, sailing around quickly eats up hours, and reaching different destinations can easily take a day or two. However, Sea Quests don't take any in-game time at all -- the guild is simply deposited right at their destination for the Boss Fight, then returns to Armoroad for their rewards without any time elapsing. In fact, the clock even reverts to whatever time it was when you started the quest even if the battle took a few in-game hours!
 * In Sea World Tycoon, a cycle of day and night is equivalent to the game's month.
 * Hydlide III (also known as Super Hydlide) featured day/night cycles, along with the need to eat and sleep.
 * Some Might and Magic games have an internal clock which is used for determining whether shops are open, how long you have been without resting and a few timed missions. It runs a lot faster than realtime.
 * War Craft 3 had a in-game timer, as well. It affected the Night Elves the most, as they could shadowmeld only at night, could research night vision and their Moon Wells only recharged at night. It also affected healing rates for humans, orcs and Undead. Finally, it affected all races via NPC behavior: Most NPC monsters (not CPU-controlled armies, scattered enemies to kill for money and hero XP) fall asleep at night, meaning they would do nothing until you actively attack them.
 * Gaia Online originally had a 2:1 Day/Night Cycle, though this was sped up so that a full 24 hour cycle takes about two hours. This is fairly important, especially in zOMG!. Certain enemies only appear at night (including one mini boss), you can only talk to the Surfers during their nightly bonfire party. (And even then you only have a portion of the whole night, because even they need to sleep), and certain events are only possible at night. (You can only trick or treat at night, for example.)
 * In Mabinogi, every ingame day lasts 36 real minutes, with more mana regeneration during the night, and Part Time jobs happening at various times in the day. Each real day means an ingame month, which special effects for each of them. Each real week equals an ingame year. And logging in on Saturday after noon (according to the server) ages your character by one year.
 * In Final Fantasy XI, one game day is slightly less than one real life hour. While this can make waits bearable, don't think about what this means when a player is in an XP party for several real life hours straight, or the fact that a "decade" passes in 20 weeks with nobody having visibly aged. It doesn't help that storywise, it's perpetually 20 years after the Crystal War that spanned 862 through 864 (or perpetually 863 while you're in the past), despite what the game clock might say, and the story missions work on a Take Your Time basis.
 * In Pathologic, one in-game minute is roughly equivalent to five real-time seconds. Due to the fact that your character walks at a snail's pace and the entire game is a brutal Timed Mission, the clock can make things quite difficult for you.
 * Xenoblade has the usual 24-hour clock with one second being usual one minute, and most named NPCs are only available at specific hours and some monsters only spawn at specific time of the day. Considering how many NPCs there are and how many of them have sidequests associated with them, it's a mercy that you can change the ingame time at will. There's also an ingame achievement called "Happy New Year!" for seeing a total of 365 sunrises.
 * In Half Minute Hero, one day takes 30 seconds, and the day is generally divided into a "morning" half and a "evening" half, with certain events only showing up at certain portions.
 * In the Commodore 64 version of Alice in Wonderland, time passed very quickly, some events only occurred at certain times, the people you talked to could return later if you offended them, and how long you took to finish the game affected your ending. (Fortunately, pausing the menu also paused the clock.)
 * Uncharted Waters had a day-night cycle but only out at sea. The only effect that time of day really had on gameplay was that you couldn't attack other fleets at nighttime, so it was mostly used just to keep the number of days you spend at sea (and the amount of provisions you have remaining).
 * Chu Lip: Time passes at an accelerated rate; different NPCs are active at different times, and certain events only happen at certain hours.
 * Ryzom has a day/night cycle, and a cycle of seasons (4.5 real-time days for a season).

Turn/Event/Plot-Induced Time Advancement

 * In Half-Life, whether it be day or night seems to not depend on anything other than plot. Either that, or Ravenloft is located in a place that doesn't have a normal 24-hour cycle.
 * In Betrayal At Krondor, time advances with each step you take. Stand still and time will stand still.
 * Crysis begins in pitch darkness at night. Less than 20 minutes into the game, you crest a hill in brilliant sunshine. Granted, sunrise can be fast, but 20 minutes?
 * Rule of Cool: The developers wanted a night drop but also wanted to show off Crysis' top-of-the-line breakthrough graphics engine. It worked.
 * Kingdom Hearts: 358/2 Days is, as the title suggests, constrained to slightly under a year as far as the plot goes. And in story mode, time really does keep on slipping-you can only do one mission per day, and sometimes the game will skip two or three weeks at a time (raising the question of Fridge Logic: it's mentioned that they get precious few days off, so why don't you get experience and mission rewards for the missions Roxas goes on while you're watching the days counter rise?). But until you've done your mission for the day, time is locked in place-you can faff about in the shop, redo previous missions in the holo-room, or just sit around staring at the wall for hours on end and time will never advance.
 * Which adds Fridge Logic of why the survive for one minute mission takes all day.
 * Persona 3 and Persona 4, mostly due to your protagonist's regular schedule of Wake Up Go to School Save The World. The game announces when the "clock" progresses to the next time of day (or the next day).
 * Very strange in Persona 3. Feel free to take the monorail back and forth across the city as many times as you want while doing Fetch Quests; it takes no time. But leave your dorm on Sunday, realize right outside the door that you forgot to do something, and try to go back in? The act of walking through the door will take all day, and it'll be evening by the time you make it inside.
 * In the Freeware Game Survivor: The Living Dead every single gameplay mode is tied to a clock (except one short area in the story mode), when the timer runs out you get rescued. The final unlockable mode has no rescue, and you must survive until sunrise.
 * Touhou Eiyashou: Imperishable Night starts off explicitly at 11:00 PM, and your goal is to reach the end of the game and restore the real moon in time for a festival by 5:00 AM. Depending on how many time icons you collect in a stage, time will advance either by 1 hour or 30 minutes. Using continues also adds 30 minutes.
 * In Devil Survivor, each of the game's eight days starts off typically around 9:00 AM. Doing an event marked with a clock icon advances time by 30 minutes. You can also skip time without doing anything at certain points in the game; in fact, at one point late in the game, if you make certain decisions there will be no time-advance events and the game will point out the "skip time" feature. Typically, each day ends around 7:00 PM (due to ) and then the game jumps to 10:00 PM (since email only works at night and in the early morning).
 * Every turn you take in any Heroes of Might and Magic game counts as one day in game time.
 * Dragon Age II has a player-controlled day-night cycle, but only inside Kirkwall (all outside levels have a permanent noon going on): Kirkwall-by-day and Kirkwall-by-night are two separate sets of locations with similar architecture. Most quests and merchants are available at daytime, while some shady quests and lots of Level Grinding against the local gangs are done in the night. Occasionally, the game will fast-forward the cycle from night to day after you exit a particularly expansive nighttime dungeon, in which case you get to see a beautiful sunrise. However, you can always Take Your Time, even when someone claims "We must be there tonight!"
 * The Expansion Pack to Dragon Age: Origins, Awakening, occasionally treated you to a sunrise or sunset in the Vigil's Keep exterior. This "cycle", however, appeared completely random and because the place was about three steps wide, most players would just miss it.
 * Time in Final Fantasy Tactics goes very quickly: one day goes by for every location passed by or battle fought within, which means that decades can pass in game if you decide to go Level Grinding.
 * This can get particularly amusing if you spend a great deal of time level grinding in Chapter 1, which consists entirely of an extended flashback.
 * In Legend of Mana, time passes similarly to the Final Fantasy Tactics system: one day passes for each location traversed or entered and effects Mana levels, but it's just about impossible to figure out what that actually does to the gameplay without a walkthrough.
 * Performing actions in Tombs and Treasure advances an in-game clock between dawn, noon, dusk, and midnight. However, you can only know for yourself what time of day it is by possessing the Sun Necklace, since the graphics themselves never change to reflect it.
 * In Scratches, there's a grandfather's clock that only advances whenever a puzzle is completed.
 * The page quote comes from the old Penguin Software text adventure Transylvania. Starting the game, you're told a clock has struck midnight. After making a given number of actions, it strikes one, then later two, and so on. Once it strikes six, the princess Sabrina you're tasked with saving dies, ending your game.
 * Mario Party 6 has a turn-based day-and-night system. Every 3 turns, the time of day changes. Depending on the time of day, certain routes will become available or unavailable, prices at stores change, and some board events will be different. Even some of the minigames will have altered gameplay.
 * Uncharted Waters II additionally introduced quasi-player controlled day-night cycle inside ports: entering and exiting any building randomly advanced the in-game "clock" by 0:40, 1:00 or 1:20 hours. Most ports also had an inn where you could stay until the next morning. While most shops were closed during the night, some offered their premium stock only after 2 am.
 * Sentimental Graffiti: Time advances in different amounts based on what you do. Traveling to distant cities take longer than close ones, and some dates last longer than others.
 * The game Sid Meier's Colonization takes place over a period of 300 years, with each year being a turn. One year typically takes only a few minutes. Oddly enough, you, the leader of your homeland and the leaders of the other nations/tribes don't get older or die during this time.
 * Ditto, of course, Sid Meier's Civilization (4000 BC to usually 2100 AD with increasingly slower increments) and Sid Meiers Alpha Centauri (400 years = 400 turns). At least the latter has the excuse of the faction leaders dipping into the Rejuvenation Tanks for a couple months out of every decade.
 * At least one Civilization game had, at the ending screen, some Roman number after your name (Yourname XI the Great), implying the leaders just pass down power, whether it makes sense or not.
 * Enduro, by Activision for the Atari 2600, also had day and night, though Enduro's night was based on how far you were into the course and not on time.

Unsorted

 * Ephemeral Phantasia