The oldest-known custom levels have been recovered.

[namida]

As far as I can tell, the oldest custom levels known to exist are "New Year Lemmings 1991/92", a hacked version of Lemmings on Amiga with 5 levels.

A discussion on Discord sparked a search for the oldest custom levels, and this was the result. I've managed to extract these levels.

They don't look like they're very good. (EDIT: After actually playing them, I'd say the 2nd one is decent, the rest are pretty meh.) They're mostly a matter of historical interest more than anything else, but here they are, in both DOS LVL format (adjusted to fit the normal graphic set numbering scheme) and in the form of a NeoLemmix pack - take your pick. The NeoLemmix version has the usual pack-structure elements added, but the levels themself are unmodified aside from converting them to NL format.

[EricLang]

Interesting!
There are a few things I would like:
Where can I find the NL level format?
Could you provide me with the original LVL files or DAT file?
Thanks in advance. BTW In the not so far future I will have a look at NeoLemmix.

[namida]

There's no DAT file, but you can get DOS-format LVL files attached to the original post. The only change from the versions in NYL91/92 is the graphic set numbers (ie: the bytes at 0x001A-0x001B in the LVL file), which I've changed from the original numbering scheme (OhNo scheme) to the usual custom level numbering scheme (CustLemm scheme); aside from that, they're directly ripped, byte-for-byte, from an ADF file of the New Year Lemmings 1991/92 disk.

Check the "NeoLemmix Tutorials" board, or "LemLevel.pas" in the NeoLemmix source code, for details of the NeoLemmix level format.

[EricLang]

Ah greet. Nice to see there is some loose stuff sometimes at the left side.
Can you confirm that Do or Die has no skills? It solves itself :-)

[Minim]

Nice find, namida! I played and solved all of them on NeoLemmix. I enjoyed those, although I'm not sure how good these are for challenges...

Can you confirm that Do or Die has no skills? It solves itself :-)

Certainly! Here you go.

[EricLang]

I cannot find the latest neolemmix source code

[WillLem]

As far as I can tell, the oldest custom levels known to exist are "New Year Lemmings 1991/92", a hacked version of Lemmings on Amiga with 5 levels.

Nice! Here are my replays.

Interesting that the first one was an automatic solver... I'm guessing that must have been a test level to see if the editing worked.

Levels 2 and 5 are quite fun to make your way through, 3 definitely needs more decor! It must have been quite difficult to put these together at the time.

[Proxima]

I played and solved all of them on NeoLemmix. I enjoyed those, although I'm not sure how good these are for challenges...

Level 1 has no interest since there are no available actions. Level 3 is only of interest for max saved (90, not 89) and Level 4 doesn't have much.

Levels 2 and 5 are both easy to save 100% but could be interesting for skills you can't live without or minimum skills.

[Proxima]

Eh, why not I'll go through this set for as many challenges as I can. Since it's so short, that shouldn't take too long; only Level 5 will be annoying.

(All my results are from playing the set in NeoLemmix, though I imagine DOS results will be very similar for most of these.)

Max saved: 50/50, 50/50, 90/100, 74/75, 10/10

Skills you can't live without: 1 - none
2 - 1 builder. It's easily solved with builders/bashers/diggers only. Diggers can be eliminated by holding the crowd between blockers, and mining down before the zapper trap. Bashers can be eliminated by building over everything and mining down at the end. For 1 builder, go under the water and use interrupted bashers to get back up. It's not possible with no builders because of the gap after the zapper trap.
3 - 1 bomber, 2 blockers
4 - 1 blocker, 7 builders. Either the bomber or another builder can be used to release the crowd.
5 - Solvable with builders only until the very end, and then you can choose any destructive skill to get through the "2", so only builders are necessary. Finding a minimum number would be a pain, though.

Skills you need for max%: Level 2 seems to need 2 builders now, although I'm not convinced 1 is impossible.

Undamaged: 1, 4

Skills to one lemming: (1), 2, 5

One skill per lemming: (1), 2, 3

Skills to lemmings facing one direction: (1), 2R, 3R, 5R

Don't turn around: 1, 2, 5

Min skills: 0, 8, 3, 9, no idea Level 2 with 8 is only just possible!

Min skills for max%: 0, 12, 3, 9, don't know

Min skill types: 0, 2, 2, 2, 2. Builders/miners works for Level 2, the others are obvious. (Level 5 is not possible with builders only and the nuke; there aren't enough lemmings to break through.)

Min time: Level 1 - 0:23.47
Level 2 - Under 2 minutes
Level 3 - Under 2 minutes
Level 4 - Under 2:30
Level 5 - My best time is 4:31.29. Would have been nice to squeeze under 4:30, but this is an annoying level and I don't feel like redoing it.