Goal:
The goal of this TAS is to beat all 30 levels of the Fun rating without access codes while going as fast as possible, with no care for how many Lemmings are saved as long as it is enough to continue to the next level.
Versions:
There are 3 versions of Lemmings for MsDos, these are categorized as "Floppy", "CD" and "CD Music"
- Floppy
- The original version of the game.
- CD
- The same game as Floppy but distributed on a CD, when putting Lemmings on CD a mistake was made that increased fall height by 3 pixels.
- CD Music
- Exact same as CD, but has higher quality music, however it is quite rare.
Lemmings on MsDos never got 1.0/1.1/etc releases, that is why we distinguish them by names, rather than numbers.
The CD version was chosen for this TAS because the higher fall height saves a little bit of time in a few levels.
Graphics Mode:
Lemmings provides two graphics modes, VGA and EGA, this TAS uses the VGA graphics eventhough the EGA graphics have faster fades, and therefor save some time.
However EGA looks meh and at times pretty bad even, so I made the choice to use VGA to provide a nicer looking TAS at the cost of some time loss.
Timing:
This TAS uses RTA timing. RTA timing for Lemmings starts on the input to start the first level (frame 150), and ends when pressing escape on the last level (frame 101453).
Lag:
The Dos port of Lemings has close to no lag at all, though it depends on system specs, and it's possible that with some tweaks to the sync settings it might run even better and maybe emliminate the short load times, unfortunately I did not think of checking that before starting this TAS.
Tricks:
- ESC
- a level can be exited at any point using the escape key, this is done in every level to save time. Levels can be exited one tick before a Lemming is recognized as saved and it will still be added to the end result.
- Fall/Jump Reduction
- Lemmings jump up a wall between 3 and 6 pixels tall, and fall if a ledge is 4 or more pixels above ground. When jumping or falling Lemmings don't move toward the goal, using bridges or some form of digging often improves the time in levels since Lemmings will spend more time going toward the exit, but in certain cases it also doesn't matter at all due to various reasons.
- Stretch Bridging
- using multiple builders at the edge of the previous bridge gets you over gaps quicker while also reducing fall height in many cases. This has multiple variations from just having enough lemmings to build a lot, to using percise exploits to free previous Lemmings to carry them to the end of the bridge over and over again, and everything in between.
Exploits:
- Basher/Miner cancel
- stoping a basher or miner mid-stroke makes them stop removing terrain at whatever step they where in the animation, making it possible to create staircases inside terrain.
- Blocker cancel
- a Lemming can be stopped at any point by assigning them as a blocker, doing this while the Lemming is in mid-air makes them walk immediately.
- Air Stand
- when a climber gets up and there is no floor for them to stand on they will still stand and be assignable for one tick.
- Climb Mineing
- using a very percise positioning setup it's possible to position two climbers in a way that when one of tem gets up (see Air Stand) they can be assigned a miner exactly when the other climber will start climbing right as the wall is removed, at which point the previous miner will catch up to the new wall and the cycle repeats, this can in theory be repeated enlessly and makes a pathway upwards that doesn't even have any steps that require jumping in it.
- Ceiling Cancel
- when very close to the ceiling of a level bashers and builders stop after one punsh/one stair, this can be useful sometimes, although it's very rare to see.
Glitches:
- Blocker Clip
- if a blockers hitbox intersects a wall any Lemming that can get to the side of the blocker facing the wall will be able to just walk through a small amount of the wall, on small walls they can even run fully through them.
- Wallzip
- when a Lemming runs into a wall the game checks the height of the wall, if it is between 3 and 6 pixels (inclusive) the Lemming will jump, however it does not check this after the Lemming starts jumping, making it possible to create a tiny gap and then fill that gap while a Lemming is jumping, making them jump infinitely high.
- Hitbox Override
- when placing a blocker its hitbox will override any other hitbox, getting another Lemming into a blocker hitbox will let it do actions such as digging even when they shouldn't be able to since the hitbox that prevents them from doing it has been overridden.
- Double Digging
- when a Lemming doing a skill is in the cursor it will be prioritized over others, when trying to assign the same skill other Lemmings will be used, however seemingly only for diggers, if a Lemming digging is in the cursor, and another digger is assigned certain hitbox checks are skipped for one tick, this can be used to destroy steel nearly anywhere as long as you have diggers.
- Destroying Steel/OWW
- steel and one-way walls can be destroyed in multiple ways, commonly this is done by using hitbox override, double digging, assigning or exploding a Lemming outside the hitbox, or abusing that when the Lemming isn't covered enough on the lower half by the hitbox it can simply ignore it (this only works with bashers).
- Nuke Glitch
- when activating the Nuke the game will use the number of Lemmings that have so far entered the level as if that's all and calculates percentage based on it, an example is having 80 Lemmings in a level and activating nuke after the second one gets out and somehow saving one in the 5 seconds time limit, the game will consider this 50% saved, because it thinks 2 is all the Lemmings in the level.
I would also like to note the glitch that happens at the beginning of levels sometimes, where you can hear the sound of a Lemming entering the exit. To my knowlage there is no known reason why it happens.
Input Density:
Like most version of Lemmings, this version is rather slow input-wise, a Lemming can be assigned on any tick, however when assigning a Lemming you can't assign another on the next tick,
this makes very input dense solutions not possible, even if they may be if the input was faster. Changing skills works the same way, although sometimes you need to wait 2 ticks after changing a skill to change it again.
Release Rate Cycle:
Changing the release rate works on a sort of cycle that determains how much can be changed on a certain step maximum, between 3 and 5, this is important because the release rate isn't updatable on every tick.
This can make tiny differences, usually 1-2 tick, in how fast a Level can be beaten.
Thankfully this cycle can easily be manipulated by inputting F2 (release rate increase) while the Level is fading in, before it accepts input, to provide optimal release rate raising in levels where it matters.
Release Rate Speed:
While the release rate displays numbers from 1 through to 99, only every second step of these actually increases the release rate. For example: 98 and 99 are the same, and 2 and 3 are the same.
Hitbox Positioning:
Hitboxes work on a 4x4 grid, they can not be just anywhere like terrain can, this can be exploited in cases, like by placing a blacker pixel perfectly on a 45 degree slope to make Lemmings walk through it, however it can also sometimes mess things up.
This is also relevant in wheather Lemmings can be blocker clipped through/into a wall.
Cursor Positioning:
The Dos version of Lemmings has limited cursor percision, it seems to be on a 2x2 grid, but I'm not fully sure on it, and none of the modern Dos ports have this, so it's never really been messured to my knowlage.
This impercision leads to some things unfortunately not being doable because things just don't fully line up.
The floppy version has High Performance Mode, which makes it much more accurate, however that mode is slower in other ways in my testing, and like previously stated, does not have increased fall height.
Level Comments:
These are small comments, explanations or thoughts that I had for each level. These are not in-deapth explanations, writing full explanations for each level would get insanely long.
Level1: some release rate managment to make Lemmings enter the level at optimal times, but not much noteworthy otherwise.
Level2: nothing noteworthy, except the 12% saved in a level that has 10 Lemmings, this is nuke glitch, although it doesn't matter for this level and is just done because it's funny.
Level3: each of the blockers here it pixel-perfect, additionally nuke glitch saves about 4 ticks here over not doing it because you need to wait one less Lemming getting out.
Level4: just some release rate management, nothing special here otherwise.
Level5: nothing special, just chaining bashers, and ensuring to hit all pixel perfectly on the grid.
Level6: combining just enough Lemmings into a group allows to blocker clip through the tiny wall, this strat is only faster because of nuke glitch, without it the waiting time to get a bunch of Lemmings on one spot would be so long that the normal way would be faster.
Level7: some release rate management, and some percise-ish builder placements. Nuke glitch here saved a tiny bit of time, but not a lot.
Level8: this is the fastest level in the entire game, nuke glitch saves about 18 seconds here. It is possible to do this with one Lemming, but limited input density makes it slower.
Level9: the first instance of fall height reduction, saving about 5 ticks in this case. On SNES this level can actually be maxed (meaning 0 falling 0 jumping) but due to Dos having 80 Lemmings maximum, rather than 100, the strat to max it builds too slow.
Level10: another nuke glitch saving a little amount of time, this can be done with just two, but it requires pausing and is therefor slower.
Level11: the first time steel is destroyed, this uses hitbox override to get an initial Lemming into the steel, then double digs to get just far enough down, and then abuses a common missing hitbox at the bottom of the one-way wall to not be covered up by hitboxes too much and be able to dig through.
Level12: very small fall height reduction at the start, and then using a lot of skills to get through the the block without leaving any Lemmings behind, there is also jump reduction on the stairs infront of the block, and building over the gap to reduce more falling and jumping. The builders at the end are stopped with the first instance of a very skill efficient basher + blocker cancel combo.
Level13: this is the level that really changes with increased fall height, completing it without using a single skill.
Level14: very heavy management of skills in this one, and the first instance of a wallzip, two actually, due to some physics differences that change how skills can be conserved on Dos this is much faster than going through the block fully.
Level15: by far the longest level in the TAS, but it's nothing too special, kind of just the same as Level14 but less heavy on skill management.
Level16: nothing too noteworthy until the very end, the wallzip setup done here is very percise to save just about a few ticks.
Level17: a very good example of how broken double digging is, other than that it's just reducing jumping and falling some.
Level18: every bomber is perfectly timed here to reduce the most amount of falling possible.
Level19: a looong boring path of walking, at least it has a pretty cool wallzip at the end.
Level20: reducing the fall height across the path is the primary objective in this level, other than that there isn't much flashy happening.
Level21: I wish I could have reduced jumping and falling on those roots some more, but it's already so tight on skills and timing that I couldn't do all.
Level22: really like this one, there is a nice amount of skill management and a cool looking exploit at the end without being too much to the point that it becomes annoying.
Level23: really tried my best on this one, but unfortunately it's quite a slow level on Dos. It's really just a lot of sill conservation, which Dos is not the best at.
Level24: due to a bug in the Dos version of Lemmings the fall height can't really be reduced by going further to the right on the one-way wall, because only on the Dos version you can't really mine a one-way wall even from the correct direction, so I ended up going sort of on the side of it, going through the top with some extra stuff would end up too slow to pull off the end and overall lost a tiny bit of time in my testing.
Level25: nothing crazy.
Level26: this second part lines up really unfortunately on the Dos version due to the shorter bashers, other than that it's just like other versions.
Level27: nothing noteworthy that hasn't been explained yet.
Level28: this is similar to the strat used by the Genesis TAS, but I optimized it with much better timing, and using ceiling canceling at the end.
Level29: not much special, going through the top at the end is much faster than going through the top.
Level30: absolutely the most underwhelming level to end on.
I tried my best on all of these, and I think it tured out pretty good overall.
References and Testing Tools:
Testing solutions and visualizing hitboxes can be done with modern versions that emulate the Dos port, such as Golems, that can use the exact level data as the original and are very accurate physics-wise.
Golems also provides TAS-like tools and visualizing hitboxes which made it a helpful reference and testing tool throughout the creation of the TAS.
TASing process:
The entire TAS was made in BizHawk's TAStudio, since it provides the most percise way to give input.
Dos Lemmings has no relative inputs, and plays very nicely with modifying previous input and almost never fully desyncs from it, even if it does, fixing the desync is very straight forward.
This is part of the reason why the rerecord count is quite low, reTASing a section of a level requires barely any, if any, reTASing of following sections, and also makes the TAS quicker to optimize and create.
For individual level times take a look at this spreadsheet: https://docs.google.com/spreadsheets/d/1J__9nJkiHzgswt_AuK9AGTIN4aGkbPheytc_LsHGwT4/edit?usp=sharing
Also thanks to two of my friends for proofreading this to try to make it as understandable as possible to someone who has no or only basic knowlage of Lemmings.
- Emulator: BizHawk 2.11.1, default settings.
- SHA1:
E12C7CF80EC774B28213BEC8BB91169D
The CD version should consist of two files, a .cue and a .bin, place them in the same folder and load just the .cue file into BizHawk and it should load the game correctly.