Glitches in Lemmings

[namida]

Do not look at NeoLemmix code as a reference for L1 physics in any way. NeoLemmix is a completely seperate engine which is intended to remove glitches, and targets custom content. Very little of the original Lemmix code remains, at any rate.

Instead, look at my modified versions (so-called "V29") of Lemmix here: https://www.neolemmix.com/?page=download_list&program=42 (Last download is the source code)

I believe another user here has made a few further fixes, using said source code as a starting point, too. EDIT: Yep, this is the topic you want to look at for that: https://www.lemmingsforums.net/index.php?topic=4973.0

[EricLang]

Thanks! I was wondering about the correctness of using the global "Paused" state of the game. method IncrementIteration().

[Gronkling]

On megadrive\genesis, if more than one bomber explodes on the exact same frame, only one of them will cause any change to the terrain, the others will blow up as if they're in a steel area.
(currently untested on other platforms)

[Minim]

Nice find! Fortunately this doesn't happen in LemmixPlayer, as the replay shows that terrain is destroyed from the two bombers with both lems dying. We've yet to see if this happens on DOS though.

(To perform this trick correctly, assign the second bomber on the second frame the 4 is shown in the countdown to allow a falling bomber to detonate at the same time as the walking bomber.)

[namida]

Nice find! Fortunately this doesn't happen in LemmixPlayer, as the replay shows that terrain is destroyed from the two bombers with both lems dying. We've yet to see if this happens on DOS though.

(To perform this trick correctly, assign the second bomber on the second frame the 4 is shown in the countdown to allow a falling bomber to detonate at the same time as the walking bomber.)

I spent some time earlier trying to reproduce it on actual DOS, as my gut feeling was that if it did happen on DOS, this would be one of those rare cases where Lemmix did not reproduce it accurately.

But no - this glitch does not happen on DOS (Amiga is untested, I'll leave that to someone else).

Video: https://www.youtube.com/watch?v=UX7fs4ORvfg

In particular note the fairly easy setup for it here - RR 74, then assign two consecutive lemmings bombers on the frame they spawn, and make sure the second one is falling when he explodes (but the first is not). This setup should allow for testing it on various other platforms, too.

[Simon]

Attached is another repro of DOS L1 with two simultaneous exploders, they produce two craters. Tested with exploder assignment during nuke.

-- Simon

[Gronkling]

Whilst I was setting up a recording of this glitch, I accidently found a DIFFERENT MD/genesis bomber glitch!
If a lemming explodes as it is falling below the level, it will play an oh-no sprite rather exploding instantly like a normal faller. In the video I do this one the first frame it occurs as it looks most impressive, however it works at any point below that too, and from greater heights.

Here's a video demonstrating both
https://www.youtube.com/watch?v=LT4P7Z9iDrA

[Zaphod77]

Pausing for time glitch as i understand it is that the timer that decides when the hatch opens still runs while the game is paused.

In Amiga, that timer doe stop when you pause.

But in DOS version, the "it's time to open the hatch" timer will still run when paused. so f you wait two seconds, the hatch will open immediately when you unpause.

the number of pauses doesn't matter. just whether any are before the hatch opens.

[Gronkling]

Builders are able to clip horizontally through walls when at the maximum height in the megadrive/genesis port

https://www.youtube.com/watch?v=u5pH1VL81ic

[The Tomato Watcher]

Alright. Maybe this one doesn't fit with the rest, since it's not really a physics-related glitch, but it's too interesting for me not to share, and after all, it is a glitch in Lemmings.

This one is on the Amstrad CPC version, and I call it the Cursor Glitch. The setup is rather specific but the execution is simple. Find or make a spot where a lemming is almost at or is going to the top of the level. The terrain can't go to the very top of the level, as it will act as a ceiling when climbing or building; it has to stop just before the top, so the lemming has just enough room to hoist or ascend. If you use the locking feature on this lemming, it should force the cursor out of bounds, or, if you're a couple pixels short, a digger or miner will nudge the cursor upwards (for some reason). Be sure to move your cursor or make sure the lemming dies before coming back onscreen or the glitch will end. You'll notice that the cursor is leaving a trail of ghost images all over the level at this point, and that you can't move it down (or possibly other directions, depending on the circumstances). These ghost images actually act as terrain, by the way. If you move the cursor directly upwards, it will reappear normally at the bottom of the screen and the glitch will be over. If you keep moving your cursor around out of bounds, you may cause some weirdness to happen. Move it in just the right way, mainly at the very top of the screen, and you will utterly break the game. Possible effects include ridiculous lemming counts, teleporting hatches and exits, ridiculously high time limits, missing or incorrect animations, severe graphical glitches, huge surpluses of skills, an infinite loop of binding your keys, and of course, crashing the game.

The effects depend on how you move the cursor, which skill or skills, if any, you assigned to the out of bounds lemming, whether you're playing on disk or tape, what level you're playing, and more. Below is a collection of examples of just what can happen with this glitch. They are all in Mayhem 1, but it looks like there are a few other levels where you can pull this off, one of which being Fun 13, where I got somewhat different results. I would NOT recommend watching the tape version examples if you have photosensitive epilepsy! There are many flashing lights in the form of severe graphical glitches and loading raster bars.

https://youtu.be/l8W28Gq_4-8