Due to the poor monster AI, monsters could potentially hurt themselves walking up the stairs under those zapper things.

How is this a bug?

Who said it is?

Seriously though, this needs fixing. You can't rely on monstes' AI here. That's why damaging floors in Doom only hurt players.

You?

Sorry, I should rephrase my sarcasm a bit: Why not allow these to damage enemies? It'd be fun to lure enemies into them. That's exactly what I'd try to do upon entering that area -- finding out they only damage players would be a bit of a slap to the face.

I have to admit, luring enemies under the zappers and making them get hit by those things is quite fun.

You know what? Mods, feel free to tag this as "fixed" if you see it appropriate, because I don't have an issue with it anymore.

The zappers really need better sprites though.

Yeah, they could use some edits. Not a bad base, but there are stray pixels everywhere.

haha I had literally no idea what I was doing when I put those there

This can be closed, since the original issue is no longer an issue.

As for the sprites, CaptainToenail has opened a bug report about the zappers needing sounds and sprites/sprite editing here.