A lot of backtracking, shortage of ammo, tight corridors that get the monsters stuck and very confusing.

Found the end because I was intrigued with the pilar portal.

I've just opened the pillar portal, but it doesn't seem to do anything. When I pressed the two buttons, there was a message saying "Main Slipgate and Gold Key accessible", and the stone pillar retreated leaving the teleport pillar behind, but (A) I see no gold key, and (B) the teleport pillar just functions as water, not actually teleporting me.

Is this a bug, or am I missing something?

Oh, I see. The opening of the portal pillar is a red herring, and the real effect of pressing the two buttons is to open a door in the room that has the gold-key door.

... and done. Turns out that the teleport pillar is the end-of-level exit, but it's not activated till later in the level. That's actually quite a nice idea, but there's nothing in the visuals or even the text prompts to communicate what's going on, so it falls flat.

Still, I found this OK. I enjoyed the claustrophobic sense of the decent into the dungeons, though that was a bit spoiled by the over-bright lighting. I enjoyed how you could avoid some of the combats almost entirely by just standing near a narrow door, taunting shamblers and fiends that can't get through, and waiting for them to kill each other. It's crude, and it's a crazy unrealistic layout, but it's fun.

OK-ish id-like map.

... Could have used a bit more polish, and it's architecturally not as compelling as id maps, but it was a fun ride nonetheless.