I was looking around the maps to find out which one is the correct one - some levels exist 5 times in the level data - and I found two maps for level 4, one with a giant secret area I didn't know about, and one without. Turns out the one *with* that area is the actual level. I don't think anyone ever actually went to that secret though? I think the entrance is as in this picture. Probably triggered by the switches on the inside of the room? I think you can access the right one through the wall.
Haven't got a game in progress so not easy to check. Lemme know if anyone tries it.
Haven't got a game in progress so not easy to check. Lemme know if anyone tries it.