Possibility of a Method to Edit Amiga Lemmings?

[spud]

Try http://alice.poddle.net/~spud/lem/Level000.zip" class="bbc_link" target="_blank">this in your LemmingsHD install.

The levels you want are Tricky 01, Taxing 15, Tricky 14 and Tricky 20. They are a random selection from Van Clan Lemmings.

Here's a teaser:

http://alice.poddle.net/~spud/lem/custom_lemmings_amiga.png" alt="" class="bbc_img" />

[Dullstar]

Woah, did you actually get that to work?  How'd you do it?

[spud]

It involved running the uncompressed level pack through ByteKiller and then a bit of messing about with the file header and footer, but yes it seems to work!

If anyone wants I could write a brief howto, so other people can try it out for themselves.

[Dullstar]

That would definitely be quite nice, since the Amiga version was quite a great version.

[geoo]

Ah, so you found a way to re-compress the data. This was the previously unsolved problem.

When Steve and I started with 2P Lemmings on the Amiga over Network through Kaillera, we got interested in whether it'd be possible to insert one's own levels, and I even started briefly to try figuring the compression format. But the interest subsided when we were told about and tried L++ for multiplayer.

Nice work nonetheless! How did you find the ByteKiller EOF compressor, and which version of this compression it is?

[spud]

Actually it was a coincidence that I started looking at this at all - I was originally digging around in the Amiga version of Lemmings to try to extract the sounds because several of the Windows ones sound sped up in comparison. After I stumbled upon this thread it intrigued me enough to have a look into the compression of the levels.

Anyway, what gave me the clue to the compression format was the documentation for XFD which stated that it could decompress ByteKiller compressed files that had had their headers modified or moved to the end of the files. I messed around with the Level000 file from the Lemmings hard drive installation provided by Mindless, first decompressing it with XFD and then attempting to recompress it and end up with exactly the same file I started with. After some time playing around with it I managed to figure out the required method to do this. I then just applied the same technique to a custom, uncompressed level pack (saved in .lvl format in Lemmix), plugged it into the Lemmings installation and, hey presto, it worked.

Stand by for a full description of how to compress the levels.