Brush dicks, water dicks, teleport dicks and torch dicks. Gameplay wasn't dicks, though, although in my playthrough a Fiend spawned as an oddly stoic and solid obstacle that I was forced to noclip through repeatedly to finish the map, which was odd.
Here's a few demos; first is a normal skill 2 playthrough (11:54, 2/4 secrets, 69/75 kills), the second is a no-kill 'speed' run (really big quotes there).