Character Level

Now I can finally take a level in badass.

"Wow! I feel as if I've passed some arbitrary experience value and gained more power!"

—Marcus, Fallout 2

The concept of "experience", in the Role-Playing Game, is based off the idea that people get better or even stronger at what they do the more they used their abilities. This is quantified by Experience Points, but is usually rewarded by an increase in Character Level.

In most games with Character Levels, the main character starts off with a fairly low "level", usually described in single digits (e.g. "Lv.1"). When they defeat an enemy, they receive Experience Points, and each time their experience reaches a designated threshold, the character "levels up": Their stats increase by a small amount, and they may be rewarded with new skills and abilities. This improves the character's ability to vanquish monsters, and allows the player to successfully take down larger monsters (with higher yields of experience) over time.

Generally speaking, monsters do not "level up" with the player; monsters are usually assigned a fixed experience level which remains the same for the entire game (although it may vary from one area to the next). There are exceptions, however (e.g. Final Fantasy VIII), and this can lead to the phenomenon known as Empty Levels.

Depending on the game, the increase in level may either have a predetermined effect, allow the player to invest into new abilities and stats, or a combination of the two. Some games even tried to make the process more logical by increasing the attributes the character has used most.

Like many Role-Playing Game tropes, this comes directly from Dungeons & Dragons. It occasionally shows up in other genres as well.

Finally, some games may actually use levels to restrict options. For instance, that Infinity+1 Sword may require you to reach, say, Level 500 before you're allowed to even lay eyes on it, let alone pick it up and start bashing monsters. This comes up in games where it's feasible for a level 1 character to get his or her hands on that sword somehow; typically, this would be an online multiplayer system.

Oh, and if you're looking for the game called Level Up!, that's here. And if you are looking for the show called Level Up, that's here. And if you're looking for the song "Level Up", see here.

Examples of Character Level include:

Video game examples

Action Adventure

Iji has levels for your Nanofield, but all a level does is allow you to get a 1 point increase to 1 stat. Interestingly, this isn't automatic - you have to find a special station to spend your available point on one of the 7 stats. You can also get extra points by picking up special powerups.
Played for laughs in X-Men Origins: Wolverine, where levelling up would make Logan glow brightly and let out a primal roar.
In Marvel Ultimate Alliance, Deadpool gets the best level up lines. "I gained enough experience points, and I leveled up!" "Now I'm the best at doing whatever it is Wolverine does!" (As one of Wolverine's post-Mook-kill phrases, as well as one of the character's signature phrases, is "I'm the best at what I do.")

First-Person Shooters

Call of Duty 4: Modern Warfare's multiplayer not only has character levels, topping out at 55, but once you do get to the highest level you can then go for Prestige -- resetting your character level to 1 so you can go through it again, this time with a special icon to let others know how many times you've done this (up to 10). Later games add various other bonuses for prestiging - Modern Warfare 3 gives you "Prestige tokens" every time you prestige, which can be spent on bonuses such as extra Create-a-Class slots or having a specific weapon or gadget unlocked indefinitely, even if you prestige again.

Hack and Slash

The only thing that increases when Caim levels up in Drakengard is the amount of Hit Points he has. In order to increase his damage or his magic meter, you have to level up the various weapons that are found in the game.

Mecha Games

In Zone of the Enders 2, if you defeat enough enemies, your health bar will increase slightly. But since you gain no other attributes upon "leveling up", you will still die fairly quickly if you let your guard down (especially against the Big Bad)

Miscellaneous Games

In the DS Dinosaur King game, the level(s) of your opponent's dinosaurs determine how much EXP you obtain by beating them. Also, as they level up, dinosaurs produce Move Cards, which can be equipped on any dinosaur regardless of their level.

MMORPGs

An interesting usage of this trope involves the MMO Sports game Shot Online, a golf game where you start as a Level 1 golfer, slicing and hooking the ball like mad, driving off the tee barely 150 yards. The more you play, the more experience you earn, gaining levels, and placing points to stats to straighten and lengthen those shots...
Battle Stations - levelling up gives you stat points that can be used to boost your abilities, and allows access to better ships and equipment.
Largely averted in RuneScape. Although there's a combat and skill total levels, the levels have to be gained for every skill separately.
The MMO Dark Ages handled character levels in the usual way, but it called them "insights", which at least added some flavor and an explanation as to why your character was suddenly better at something: he or she was said to have "gained a flash of insight". Later updates to the game ruined this flavor, though, by implementing a "Level Up" graphic above the character's head.

Platform Game

Faxanadu has character levels, but they only determine the amount of XP and money retained by the player when they die and resurrect.
- And the character levels are, in fact, counter-intuitive. Rather than leveling up as soon as you get enough experience, you have to get enough experience, and then make your way to a church and speak to the priest, who gives you a new title (and effectively the level). If you die before you manage to make it to the church (a frequent occurrence), then your experience points are reset to your previous title, making leveling a grueling and entirely unnecessary aspect of the game.
  - And in fact, being at high levels will actually hurt your chances of winning the game, as levels actually shorten the duration of the items that you use.
The Ratchet & Clank games feature this, in generally increasingly extreme forms as the series progresses, but for your weapons: Each time you kill something with any particular weapon, the WEAPON earns experience. When it gets enough, it levels up. Later games allow it to become a new, more powerful type of weapon at the end of a multi-step leveling sequence. Some games only allow higher levels to be reached after you unlock the hard mode of the game and are playing in it.

Racing Games

Blur has Fan Levels. As your fan level increases, you unlock new cars and new mods. In single player this is capped at 25. In multiplayer this is capped at 50 with the option to enter Legend Mode, similar to Prestige in Call of Duty Modern Warfare in that your level resets to 1 and you can go through the progression again (up to 10 times), except each Legend Mode unlocks another new car.

Role-Playing Games

The Fallout series has a fairly generic level-up system similar to GURPS (which it was originally slated to use), in which each level-up is primarily focused on allocating skill points. Base attributes do not change upon level-up, but every third level grants a perk for further customization of the player character. Your NPCs level up as well, and, as the page quote shows, they will throw in some funny lines when they do. Fallout's level system is notable for not holding the player back from wielding powerful weapons in an open game, allowing people in later playthroughs to pick up devastating weapons and armor early on with the proper know-how. This is marginally balanced by the fact that most low-level characters won't be able to pick up enough ammo or even hit anything with an energy weapon at 20% skill with it.
Despite being a card game, some Genre Shifting Yu-Gi-Oh! video games do this, preventing you from using stronger cards until you "level up" to their caliber. This has sometimes gone to the extreme, not only preventing you from using cards higher than your current level, but whose collective experience point total is higher than yours, as well, essentially forcing you to play with lackluster cards until you're more than halfway through the game.
- The card game itself has "Level Monsters", monsters that are capable of Leveling up and becoming stronger. Lower level monsters usually just need to survive a turn to level up, but destroying a monster in battle is also typical. Higher leveled monsters usually get some benefit from being leveled up from their previous level, while the highest leveled monsters typically cannot be summoned by any way but by leveling up the previous leveled monster.
  - The card Level Up can also be used to bypass any leveling conditions, it tends to be abused.
The Elder Scrolls series has a variation on this, starting with the second game Daggerfall. (Arena used standard levels.) Levels are gained in individual skills (rather than levels leading to new ones). Every 10 "major" skills (skill designated when creating a new character) leveled results in a new character level (and an increase in stats based on what skills were increased). In addition to this, more variations within a skill become available every 25 levels a character gains in that skill (for example the spell related skills allow the character to use more powerful spells, melee skills grant more power attacks and so on).
- The noted skill perks are only present on the latest two installments of the Elder Scrolls series, Oblivion and Skyrim. Skyrim also does away with major and minor skills.
In the Pokémon games, traded Pokemon may not listen to your commands if their level becomes too high, since you haven't "earned" the right to command it.
- In the Pokémon anime, this phenomenon was depicted by Ash's Charizard, who cheerfully obeyed him as a Charmander, but ignored him more and more as it evolved. It almost followed the games rules: the Charmander wasn't his to begin with (it was a castoff from some other trainer who was never heard from again) and quickly became his most powerful Pokemon (thus higher level), but the anime failed to account for the badges, which are the sign of "earning the right" to command traded Pokemon.
In Lost Kingdoms, you would only level up with the storyline. This wouldn't stop the player from using powerful cards, since you'd use HP instead of rune stones when you ran out of them (and your HP wouldn't drop to 0 from this, and exploitation fixed in the sequel).
In The World Ends With You, you and your partner go up a level as soon as you gain enough experience. The beam of light that accompanies this phenomenon has been observed to damage enemies. Your effective level is adjustable on the Phone Menu, increasing the chance of pin drops at the expense of making you weaker. There is a level cap of 100, at which point, it displays a star instead of a number, and the "Next" value is permanently 0. Leveling increases your HP and Bravery permanently (meaning lowering your effective level will not reduce them). Stat gains are achieved by eating.
The first two Paper Mario games also take a somewhat different direction. When Mario levels, he can choose between more hitpoints, Flower Points (used for special attacks) and Badge Points (which can be used to equip badges with a variety of effects). His offense on the other hand is upgraded by finding better hammers and boots, and the Star powers are plot-related. His partners don't level at all but can be upgraded twice, resulting in more hitpoints (in the second game), offense and a new move.
- Mario & Luigi: Superstar Saga and sequels have a different, albeit slightly similar variation. As well as the standard leveling up, a bonus slot machine type wheel appears and you can choose any stat to add a few more points to each time. The latest game also adds ranks which are gotten by CharacterLevels, each enabling you to equip more items/gear.
Averted (for the most part) in Monster Hunter, which is a bit of a surprise given its MMO-like structure. The character's abilities depend directly on two factors: player skill and gear. Played straight in some versions where you can recruit NPC companions who do indeed level up.
.Hack//G.U uses your character level to lock you out of higher level equipment till you hit that level.
Inverted in the first two Rockman.EXE / Mega Man Battle Network games, the first Ryuusei no Rockman / Mega Man Star Force game, and Rockman.EXE: Operate Shooting Star, their Crossover. Instead of having to level up in order to increase your abilities, your level is calculated based on the upgrades you've acquired (although Star Force and Operate Shooting Star add levels for certain postgame achievements, to round out the max to 100). There are no experience points whatsoever, and the level itself is mostly cosmetic, which may explain why most sequels dropped them altogether.
The NES/Famicom (along with its Updated Rereleases) game Final Fantasy II went the "level up only what you've been using" route, and applied it to weapons and spells as well as stats (for example, your maximum HP would increase if you got hurt a lot). Needless to say, it didn't last, although its remakes have made it less grindy and more generous and balanced, along with removing the occasional stat decreases from the NES/Famicom version.
In Infinite Space, only assigned crew members will gain experience points from battle, and when they level up, the stat required by their post will go up faster than other stats. The assignment and command skills owned by your crews will level up for each twenty levels.
Freelancer levels are based on money, except if you're still playing through the story, in which case every other level requires you to complete a storyline mission. These levels allow you to purchase mightier ships, which in turn have better armor, shields, armament capacity, and cargo space.
- The "money levels" in Freelancer are also a form of Go Wait Outside because generally your allies are getting plot-important stuff done while you go raise some cash and spruce up the ship for the next mission. It's always set at a certain amount above your current value, so you can't just grind up extra money ahead of time and skip those levels.
Knights of the Old Republic naturally does this. It's a good idea to wait until low on health before spending the experience points, as this will fully heal your character.

Shoot'Em Up

Bubble Tanks has your "levels" in an evolution tree- when you collect enough bubbles from defeated enemies, you "level up" and choose a next evolution for your tank. Careful though, getting hit by enemies causes you to lose experience points, and you can go back down a level if you are not careful!

Stealth Based Games

The early Metal Gear had leveling systems. In the first Metal Gear (and Snake's Revenge), Snake is promoted in rank as he rescues hostages, increasing not only his maximum health, but also the maximum capacity of items and ammo he can carry. In Metal Gear 2: Solid Snake and Metal Gear Solid, Snake's level increases after defeating a boss.

Survival Horror

Dead Rising uses a basic form of this: you kill zombies and take pictures to gain experience, and each level gained results in either a stat boost (Speed, Power, Inventory, etc.) or a new move (Double Lariat, Disembowel).

Turn-Based Strategy

Jagged Alliance has an "Experience Level" that increases slowly whenever the character's attributes or skills go up (no matter which skills...). It increases performance in nearly every aspect of gameplay, but does not increase the level of challenge (that's based on another, character-irrelevant value). However, more experienced characters do cost more to hire, which means that you need to watch out not to train your characters beyond your financial means.

Non-video game examples

Film

In The Gamers: Dorkness Rising, which is, after all, about Dungeons & Dragons, the characters are explicitly stated to be level 9. Which, considering their abilities, seems about right.

Tabletop Games

Exalted returns to Character Levels, sort of. It uses the WW system and allows you to buy what you want, but a character's meterstick for power is their Essence stat.
- All of the New World of Darkness games feature a meterstick for power (Blood Potency for Vampires, Primal Urge for Werewolves, Wyrd for Changelings and Gnosis for Mages). In most cases, however, this doesn't limit what powers you can buy (save for mages, where Gnosis determines just how many levels a mage can buy in their ranked Arcana).
Two of the first tabletop RPGs not to use levels at all were Traveller and RuneQuest, which relied on skill and stat advancement entirely.
Averted in GURPS. Characters slowly gain Character Points that are used to improve skills, powers or stats. Theoretically a character built on more points is more powerful but the system explicitly notes that even a discrepancy of 25 points is fairly minor.
FATAL apparently has levels too...although your character is supposed to die before level 20. The author considers this a good thing.
HERO System games like Champions don't use Character Levels or even a typical class progression. Rather, your Experience Points function in a manner identical to the points given at character creation, creating a more consistent curve of progression rather than the "Staircase" style of other systems. Or it could make the game needlessly complex.
Mutants and Masterminds: First edition had levels the character earned after every 15 power points. These levels in turn acted as a cap on how much a character could invest in certain attributes. Second edition loosened this up a bit, and level simply became a cap on all players power point expenditures (the cap only applies to certain categories) that could be changed any time the GM felt like it.

Web Comics

Apparently gaining a level in Goblins feels like a glow inside... and can be the result of roleplaying at the last moment to have just enough experience.
In The Order of the Stick, Levelling up is representing by an audible "Ding". Roleplaying for experience is also what comes to mind when you've just been denied killing your party's scrappy for the level
Often, lower character levels mean you get the lower end of the equipment list.
Red Mage of Eight Bit Theater lets out a barbaric howl of DING! when he "levels up".
Played straight in Our Little Adventure. The group even get a fanfare filled panel when they do level up.
- When the characters levelled up in the Rosoro Underground, not all the characters levelled up at the same time. Lenny levelled up first accidentally in this comic here.
Parodied in this Xkcd.

Web Original

The serial Memetic Narration (found here) features a third-person narrator whom the main character can hear. Said narrator informs the main character that as he builds relationships with his friends he will be alerted when the relationships "level up," a la Persona 3 and Persona 4.
In the first Asdfmovie a character levels up after randomly punching another character in the face.
Mall Fight's perception of a Character Level is absolutely distorted into oblivion. One fighter has some set stats (Attack, Defense, etc.) while another has totally different stats (Strength, Perception, etc) while another doesn't even care about it at all.