Lemmings 3 glitches

[kieranmillar]

I've been playing around with Lem3Edit and discovered a number of bugs in Lemmings 3, so thought I'd document them, one post at a time.

Bug: Can dig beyond all level borders.
Severity: Harmless.

All areas beyond the level border can be dug with the shovel. As lemmings going outside the level borders kills them, this is completely useless and sometimes will result in the lemming dying anyway, so has no consequence for the player. Note that trying to dig off of the right side of the level causes the lemming to get stuck in an endless loop of trying and failing to dig. When digging off the bottom of the screen the lemming cannot be reselected once partway off the screen and therefore this cannot be exploited to reach areas by going below the level.

See attached animated gifs for demonstrations.

[kieranmillar]

Bug: Lemming becomes unresponsive when trying to drop a tool, but can't.
Severity: Annoying, potential to cause level fail state.

When you ask a lemming to perform an action, it will wait until it is in a suitable position until it performs the action. Many of the actions seem to time out after a short while, but the drop tool action doesn't, leaving a lemming potentially waiting forever to drop the tool and not responding to any more commands in the meantime.

One simple way to set this up is to trap the lemming between two blockers or walls with exactly two grid squares between them, causing the lemming to constantly turn around. If you are able to free the lemming, it will drop the tool at its first opportunity.

See the attached animated gif for a demonstration.

[kieranmillar]

Bug: Lemming lands on bottom level border if a walk action is queued.
Severity: Harmless.

If a lemming is given the walker action, but falls off the bottom of the screen before having a change to execute it, the lemming will very briefly safely land or splat on the bottom of the level. However if it lands safely there is not enough time until it falls again to do anything and so this glitch cannot be exploited.

Another easy way to see this is to cancel a shimmier with a walk command while above the bottom of the level, as the lemming will fall with a walk command active.

See attached gif for demonstration of walking on the bottom and splatting on the bottom. Had I taken more care extracting this, I could have gotten this to loop perfectly :p

[kieranmillar]

Bug: Digging through steel.
Severity: Exploitable.

Lemmings can dig through steel under some very specific circumstances. The particular combination of circumstances are totally bizarre, but here they are:

• Lemming is digging either up and to the left, or up and to the right.
• The very first dig cannot go through steel as you are not allowed to choose to dig in that direction in this case, only subsequent digs will work.
• Just before the lemming takes a swipe, the terrain both one AND two bricks directly above his head must be both solid and diggable. This is particularly odd because the second brick above his head does not get destroyed during the dig.

When these conditions are met, the lemming will dig through steel as though it were regular ground.

This is exploitable by setting up these conditions using bricks. You can dig through a one-width steel wall by building a tower of 7 bricks directly upwards in front of the steel wall.

See attached animated gifs for demonstrations.

[kieranmillar]

Bug: Building an impassable staircase. (aka One Way brick bug)
Severity: Annoying, potential to cause level fail state.

Usually when digging or building, the conditions to be allowed to perform the action are such that the lemming has room to move into the spot where it is digging or building. So when building, the lemming must be able to stand on the brick it is going to place. However when building diagonally upwards, the lemming fails to properly check if the ceiling is high enough to step onto the brick, and as such it can create a staircase that cannot be passed in either direction.

This happens when you are right next to the ceiling, and then the ceiling raises. You can build diagonally upwards, but the ceiling is too low to step up or down the resultant brick, although the lemming doing the building manages it during construction. Unfortunately, this can result in the player not realising the staircase is impassable until much later in the level. To avoid this, build outwards one more brick before trying to build upwards.

See attached animated gif for a demonstration.

[Simon]

Excellent finds, and beautiful explanations!

I would have never suspected the steel digging, and the others are nice corner cases. The answer for level designers is probably to make 2-block-thick steel walls wherever possible.

-- Simon

[ccexplore]

Yeah, who knew steel glitches made a comeback? Nice finds! Now I had to find some time and go back to the official levels and see which ones may be exploited.

Was digging beyond all level borders something that needed the editor to explore, or are there official levels where all of it could've been tested as well?  Is the bug that normally it would only take one stroke and then stop (because there's supposed to be nothing more to remove), but at the boundary it continues as if there are still more things beyond the boundary to remove?

Building an impassable staircase could potentially be exploitable in very rare cases, specifically the ability to block other lemmings from following through the path of the builder.  Granted, in most cases you could probably just change the build direction to stacking for the same purpose instead of using the bugged behavior.

[kieranmillar]

I would have never suspected the steel digging, and the others are nice corner cases. The answer for level designers is probably to make 2-block-thick steel walls wherever possible.

Yes I discovered it by accident and then just had to figure out how it worked. Making steel walls two blocks thick will work most of the time, but you have to watch out for areas where there is regular terrain above the steel, as you may be able to build up to it then dig through the top of the steel. But that sounds very resource intensive.

Was digging beyond all level borders something that needed the editor to explore, or are there official levels where all of it could've been tested as well?  Is the bug that normally it would only take one stroke and then stop (because there's supposed to be nothing more to remove), but at the boundary it continues as if there are still more things beyond the boundary to remove?

The bug is the game believes there is diggable ground outside the borders when in all other instances it acts like empty space. Take a look at the first animated gif, the lemming is walking on steel and so in normal circumstances you won't even be allowed to choose a direction as there would be nothing to dig in any direction. But the game lets you select to dig in all offscreen directions, and which point the dig is executed and the animation + tool cost is executed despite not removing any ground. Note that the game always ignores anything outside of the level borders, for an example of this, look at the disappearing floor trap in front of the exit in Classic 3 in the editor, the lemmings will fall off the bottom of the screen in-game despite there being solid steel below the level boundary in the editor.

It is possible to see these behaviours in official levels e.g. Egypt 2, but nobody ever noticed before because why would you ever bother trying to dig outside the level edge?

Building an impassable staircase could potentially be exploitable in very rare cases, specifically the ability to block other lemmings from following through the path of the builder.  Granted, in most cases you could probably just change the build direction to stacking for the same purpose instead of using the bugged behavior.

There's an even easier way to stop other lemmings following the builder: L3 gives you unlimited walkers and blockers. I like to give L3 the nickname "Worker Lemming Deluxe".

[kieranmillar]

Bug: Psycho Buzzard Trolling.
Severity: Exploitable.

You probably already know that the Psycho Buzzard is an absolutely worthless enemy, missing half the time and being trivial to jump over. Well it turns out it's even worse, you can easily troll it out of harm's way.

When the buzzard prepares for a dive, if it cancels by having the target turn around before it gets a chance to dive, it will back up a bit and raise height. If you furiously click the walk skill on its target, the buzzard will constantly cancel the dive and back up until it is so high that it no longer targets your lemmings, or gets stuck in the ceiling.

Note that if the buzzard does decide to dive for whatever reason, it will return to its original height.

See attached animated gif for a demonstration.

[kieranmillar]

Bug: Psycho Buzzard Brick Confusion.
Severity: Exploitable.

This enemy just gets worse.

Psycho Buzzards don't understand what to do when a lemming builds directly upwards, failing to recognise that the lemming is not getting any closer. It will stay in a ready state until the target either walks back into the line of fire, or dies or exits the level, ignoring all other lemmings.

This demonstration is a lot longer, so I made a video instead of a gif. https://youtu.be/hQt-EmuCuBM

[Simon]

Beautiful showcases, thanks.

What a bugfest -- but on the other hand, the buzzard is complex and underused in the level designs. It must anticipate lemming movement precisely to strike, it's not the easiest routine in the book. No wonder corner cases like this can pass unfound until today. The potato beast is far more consistent.

I loosely remember trapping the psychobussard in its ready state temporarily, probably with walker assignments like in reply #8. It's been too long ago and I didn't investigate thoroughly back then.

-- Simon

[kieranmillar]

Actually the Buzzard Brick Confusion bug has been found before, it shows up in IchoTolot's Let's Play. It's what caused me to investigate this particular weirdness.

https://youtu.be/6vVY71xK0qU?t=2m57s

[kieranmillar]

Bug: Wolf Whistle Landing.
Severity: Exploitable.

When lemmings are caught by the Lemme Fatale monster, they perform a Wolf Whistle. If they do this in mid-air, it counts as landing on solid ground. You can use this to split a large fall in two to land safely, or splat in mid-air (admittedly less useful, but funny looking). Because besotted lemmings can be cancelled out of their death timer if the Lemme Fatale dies (bet you didn't know about this!), you can exploit this to survive a large drop if the level can be set up correctly.

See attached animated gifs for demonstrations.

[kieranmillar]

I don't even know what's going on anymore in this game.

Sadly I have no idea how to unbreak this level because I don't understand why this is happening.

[kieranmillar]

Bug: Falling into water doesn't reset the lemming's fall height.
Severity: Annoying, potential to cause level fail state.

Each Lemming maintains its own counter to see if it should splat or not when it lands, which increases as it falls, and is reset when they land. Unfortunately, if the lemming is a swimmer, he can fall any distance into the water and survive, but this does not reset his fall counter. This means the lemming is now susceptible to die from very small drops.

The good news is, that there is one way to safely reset the lemming's fall counter, and that is to enter the state where you pick a direction from using a spade or brick tool. You do not have to ultimately choose a valid direction, just enter the direction picker mode, and his fall counter gets reset. Unfortunately, no other skill or action works to do this. Level designers, take care to try and ensure the player always does this after a long fall into water.

See attached animated gif for a demonstration.

There is one other situation where the lemming checks its fall counter, and that is when to open its umbrella, but if you have already passed this distance, the lemming will completely bug out. (Note: this is the same video in the previous post).