Open any level in Copycat Lemmings, then look at the trapdoor. It is already open. Then, after the "Let's go" sound, the trapdoor then does the opening animation. This is a graphical glitch.
If you open a non-Cheapo-conversion style level, the trapdoor will be shown closed.
EDIT: Or, open a level in Lemmings Reunion / PimoLems that uses styles converted from Lemmini. The same problem occurs.
Issues with Cheapo styles - especially those that are purely graphical - are generally considered low priority, but I'll take a look when I get a chance.
The same issue happens with styles that are converted from Lemmini.
Tested it with an older version (last version with MAIN.dat) and the animation is ok there. Must be a bug from a recent release.
Looked more into this:
The Preview frames of the Lemmini styles are 1 (entrance open) instead of 2 (ectrance closed which is standard).
But as this was previously not a problem it never bothered me (seems like Lemmini conversions had a special treatment).
Now 2 possibilities:
1.) Put in the old behavior again and treat it as a bug.
2.) I redo all my Lemmini styles with the 2nd frame of the entrance as preview + rebuild and update my packs again as this ""should"" also do the trick. (would include: Sports, Shadow, Egyptian, castle, City and Epic)
Fixed for the next update.