Fun little map

So I wanted to try something. I wanted to make a small level that is balanced for Nightmare. Here's what I came up with. I actually think it's fun. See if you can do it.

http://www.mediafire.com/download/fos7q313re43pwp/GRBNM1.wad

No demo, I got through it with GZDoom and one save before the AV maze. And a number of deaths of course. Starting in view of hitscanners is kind of annoying since you'll take a random amount of damage at the start. The way it cycles through the same areas is clever, since the enemies will naturally repopulate.

The AVs often get stuck on the rising walls, I don't know if that's intentional or not. Makes that section harder, randomly, hence the save.