OK, I think I need to clarify a couple of things! The project is a mostly-total add-on pack for Lemmings 1, including new graphics, music and levels. However, most of the code from the original game will be intact (I'm patching it here and there to suit my purposes, but I don't want to change any of the original game mechanics. That would be blasphemy ;-) )
So I intend to use /some/ of the original data. That's why I would potentially require users to supply their original disks - to extract the bits I need, and combine them with the new stuff to produce the finished ADFs.
And yes, I said ADFs - this is intended as a modification of the original Amiga game, to be run on the Amiga, for the benefit of Amiga emulation fans :-)