That One Level/Video Games/Puzzle Game/Lemmings

The Lemmings series' simplistic but addictive gameplay has made it one of the most fondly remembered puzzle games of recent times. All of the games share the same small furry creatures plodding through dangerous territories, the same goal to guide all of them to the exit safely, and the same head-scratching difficulty. How difficult are they? The fact that this game needs its own subarticle under That One Level speaks volumes.

Lemmings

 * The infamous We all fall down. Unless you have the Windows version and its increased fall distance, these levels are incredibly annoying, and worst of all, you have to do it four times, saving an increasing number of lemmings each time. And worse yet, you have to save 100%. One screwup, which is very easy to do, and all your hard work is for naught.
 * Taxing 14, Hunt the Nessy. Not a hard level in terms of pure difficulty, just mind-numbingly tedious and not fun to play, unless you're the rare player who can't get enough bridge building.
 * In Taxing 21 (Feel the heat!), you have to get the Builders to make ladders in such a way that, when the Lemmings arrive to the end of the big ladder, they fall down exactly on top of the exit. If you make the ladder too short or too long, they get scorched by the fire blasters on either side, and there isn't a lot of room for error either. (Still, you can just assign the Basher skill to make your builder stop building.)
 * Taxing 23, King of the Castle, is a major pain. You have to get all your lemmings across a medium-sized gap, and you have only builders - no blockers or digging skills to keep the others penned up while you build your bridges. Even worse, you have a small number of builders with which to complete the level, and the level is designed so that you have to use nearly all of them, so you can't waste any, either.
 * Taxing 26, Triple trouble. It's Exactly What It Says on the Tin. You're given three Lemming spawn points but only one exit, blocked off by a ring of stone in the center of the stage. It's easy to save all the Lemmings coming out of the topmost hatch, since you can just dig through the upper edge of the ring, but the other two hatches are a nightmare. You have a severely limited amount of Builders (12 on most versions, 10 on the SNES and Genesis versions), and you need two of them to get those groups past otherwise-impassable steel walls and one to build up to the exit once you've Bashed away the ground beneath it. In other words, you have only nine/seven Builders to get up to the ring in the center, and if a Lemming runs out of building room when he nears the goal, you're pretty much screwed. Why this level isn't in Mayhem is a mystery for the ages.
 * Mayhem 5, Down, along, up. In that order, is a massive headache of a level. In its original version as Fun 28, If only they could fly, you have thirty Builders and can simply send one ahead to build a giant bridge for the other lemmings. But in the second version, you only have five Builders. This time around, you must use a carefully placed combination of Builders and Blockers to build a zigzag of staircases to the platforms below the exit. The precision involved in positioning the Blockers and the staircases can be frustratingly unforgiving.
 * On the black-and-white Mac version, Mayhem 14 (Pea Soup) is virtually impossible, as the "peas" that you need to build to are completely indistinguishable from the muck that surrounds them due to the port's graphical limitations.
 * Mayhem 21, With a twist of lemming please. In the level's original version as Tricky 12, Bitter Lemming, you have enough Builders that it is easy to stop the initial fall from being fatal to non-Floaters in fairly short order. But in the second version, you have just enough Builders to create the path to the exit, so all 50 lemmings must be turned into Floaters straight out of the gate. Miss one, and you have to start over. But that's not the end... once you send a lemming on ahead to build the bridges to the exit, you must bash through the wall of the pit under the entrance to reach the bridges - and you only have one Basher. Click on a lemming facing away from the wall instead of toward it - which is very easy to do - and you have to start over.
 * For the Mac version, it is of course Mayhem 26, The Steel Mines of Kessel -- due to higher-resolution graphics, some stalks on the ground were made impassable, so you have to use extra bombers to get past them. Trouble is, you're limited to eight bombers for the level, instead of ten as on other versions.
 * Mayhem 29, Save me!, is a lot harder than the final level. In particular, there are two platforms directly over the exit, and the first lemming to land on each one must begin building the instant he lands and then turn into a Blocker so that the other lemmings will turn around and walk over the opposite edge. The time window available for these actions can be extremely unforgiving on some versions.
 * There are some levels specific to the Genesis version, which has two extra difficulty settings, which could qualify here:
 * Tricky 27, Everyone turn left. You have 60 Lemmings, 60 Miner skills, a release rate of 80, and an expanse of one-way terrain pointing the opposite direction the Lemmings walk in, at the end of which lies a lava pit. The goal is to have each Lemming mine into the one-way ground so that, well, everyone turns left. However, you have to save every Lemming in this stage, so not one Lemming can get scorched or you'll have to start all over - and if you accidentally select the same Lemming twice, well... Evidently, Sunsoft decided we needed two such levels - however, Everyone turn left (Part two) is level 7 on SUNSOFT (the highest difficulty), so its high difficulty is more forgiveable.
 * Present 29, Private room available. Two lemmings, the first and last out of the gate, must forge the path through the level while the other eighteen must be separated into individual chambers and each must then dig through the very centre of the chamber floor - too far off centre and either they will fall to their deaths or they will dig through their neighbour's wall creating another fatal fall.
 * SUNSOFT 23, Move on in two separate groups. This requires a series of quickfire bashing and building manoeuvres within the first few seconds to set everything up properly.
 * SUNSOFT 27, Two heads are better. Three bombers must be activated so that they blow through three platforms in such a way that a fourth Lemming can fall through the holes and walk to the exit - get the timing slightly wrong and either the later bombers will fall to their deaths before they blow up or one or more of the lemmings will walk into a spinning incinerator.
 * SUNSOFT 29, I am A.T. This essentially requires creating a diagonal staircase of Diggers to allow Lemmings to climb out of a pit and walk to the exit -- except that as they reach the top, they must be turned into Diggers to keep the staircase climbable. Even if you get the basic pattern down, get the timing wrong (or set the release rate too low or too high) and either the final step will be too high by the time the first lemmings reach the top of it, some of the intended Diggers will fall to their deaths at the beginning of the staircase, you will run out of Diggers too early, or too few lemmings will have climbed the staircase by the time the final step becomes too high permanently (there are 100 lemmings, of which 80 must be saved). Did we mention the 2 minute time limit?
 * Sometimes the creators are particularly sadistic, giving you a 100% option, but a level where you have blockers and exploders to tantalize you.
 * Slightly weirder physics and mechanics made the ZX Spectrum Level 27 (Tricky 12), Postcard From Lemmingland, monumentally irritating. The solution turned out to be synching the release rate with a Basher such that the lemmings pass through the scoop of the ramp he digs as a small enough step to get up onto the ledge. (Setting the rate to 97 did it.)

Oh No! More Lemmings

 * Havoc 16, Scaling the Heights, requires turning the first lemming into a Blocker just before he walks off the edge of the very narrow platform under the entrance, trapping the other lemmings against a wall. After a lemming has been sent on ahead to create the path to the exit, the other lemmings must be freed by building out of the pit. Because of the difficulty in assigning a job to a particular lemming in a large group in a small area, it is extremely easy to inadvertently build over the Blocker and send all of the lemmings marching off to their deaths, without the resources to make them turn around. And, of course, you only have 2 minutes to complete the level, so the clock often ends up being your worst enemy.
 * Havoc 17, Where Lemmings Dare. The first part of the level is moderately challenging, but the endgame is where it gets rough: you have to dig a path downward and then mine diagonally so that you come out right above the exit. And it really must be right above the exit; one pixel off and your lemmings get mangled in one of the two traps on either side of the exit, forcing you to do the whole stupid level again. Oh, and you only have 2 minutes to finish the level again.
 * Havoc 18, Lemmings in a situation, is not so much difficult as long and complicated, and building the many bridges and digging through the many pillars required to get to the exit can be tricky, particularly with only 4 minutes to finish.
 * Havoc 19, Looks a bit nippy out there, requires that the first lemming build across a small gap at the bottom of a narrow pit; get the timing wrong and you won't be able to finish the level. Then, you must wait until the 79th lemming (of 80) has fallen out of the entrance and have him start building a bridge the instant he hits the ground (over the pit containing the other 78 lemmings) so that the final lemming can cross the gap and be available for other tasks to complete the level. Both lemmings must then complete a series of further precision building manoeuvres to both pave the way to the exit and free the other 78 lemmings. This time you have a whole 3 minutes to finish.
 * And finally, Havoc 20, LOoK BeFoRe YoU LeAp!. You have to use about a dozen bombers to dig a downward path through several layers of rock, but you don't get any blockers to help you place them precisely; you have to time them to explode at a certain place while they're still moving. If just one or two explode in the wrong place, you can either send them all plummeting to their doom, trap them somewhere with no way out, or simply end up falling short of the completion percentage because you wasted too many bombers.

Lemmings 2: The Tribes

 * Nearly all of the Level 10s for each tribe in Lemmings 2, as well as that fucking Highland level that made you create a ramp with thrown rocks.
 * But especially Take up Archery, the final Sports level. The entire level needs split-second timing and near-perfect aim with your arrows and javelins. The slightest error will prevent you from finishing it, and even a slightly too long pause will result in the death of a lemming and thus the dreaded silver medal.
 * Snow More Lems, the third level of the Polar tribe. The meat of the level is a twisting metal-walled passageway that you have to use ropers to create a path through. The problem is, due to the angles you have to work with and the depth of some of the pits, it's extremely difficult to shoot your ropes so that they land in the right spots. Aim too high and your anchor fails to stick, wasting a roper. Aim too low and your lemmings don't have enough room to climb out of the pits.

Lemmings 3D

 * The Hangar sticks out in Lemmings 3D.
 * Five Towers is another stinker in 3D Lemmings' Mayhem category.
 * Dot to Dot. One of the space levels with awesomely creepy music. It's a matter of building bridges from platforms labelled 1 to 12. Sounds simple enough, but this is 3D - the numbered platforms often require turners to access and loads of camera rotation to make sure you're letting your lems fall in the right direction. Miss a platform and they fall into the abyss below. To make things worse, though, the 12 minute time limit isn't enough - adjusting the release rate at the beginning is necessary to get enough lemmings to the end in time. Of course, adjusting it too much will mean your lemmings are too close together and too many will die before you get to the end.