>Help me find a wad based on vague recollections!
Let's see if such quiz will be successful. I have several of these which were bugging the hell out of me for the past weeks!

Whether of a megawad or an episode, this map was part of a bigger project.

You start inside an underground base, effectively overlooking a large canal, which you need to cross with platforming (1) or otherwise using a lift (2). Other side has square-looking decorations, either sticking out of the ceiling or the floor. Your first task here is to hit a switch on the other side, which starts a difficult ammo-deficient fight (by opening a closet with multiple barons and lowering the water level of the canal, which opens a sewer pathway with cacodemons emerging from). I remember that making these infight was crucial. There was also, supposedly, a closet with a group of pinkies, which in turn lead into a different area of unknown purpose. Question marks designate such areas of which I have no memories.

Know that any details may have inconsistencies and are in no way precise, up to me blending memories from different pwads.