So, I found a couple of quirks with the monster closets in E1M4. The demon/cacodemon in Sector 273 cannot teleport because the linedef special is not set on the diagonals.
More interesting are the closets with the stairs (tags 1,2,3). These work in vanilla Doom 1.9 and PrBoom, but they don’t seem to work in MBF 2.04. Maybe MBF only limits the stair effect to the first sector matching the tag? That would be a bug in the engine, then. I’ll see if I can contact the developer.
Edit: never mind, I figured out the problem. This is actually a bug in Boom/MBF’s _emulation_ of the vanilla Doom behavior. When disabling comp_stairs (“Use exactly Doom’s stairbuilding method), the native Boom/MBF method works.
https://prboom.sourceforge.net/mbf-bugs.html
