Ionous - A real treat for the eyes. A bit on the easy side, but theres no denying the visuals are stunning. There are some spots on the ground that have perfectly square lighting, which seemed a bit odd but didn't detract from the overall experience.
Khreathor - I loved the vending machines, a very novel idea that I took great advantage of. Good use of Quoth's breakable boxes, it always makes a map feel more alive. My only complaint would be the map is too flat, no height variation whatsoever, not even a single staircase. Save for the drop in the sewer though.
Mjb - Climbing waterfalls, who'da thought? I'm sorry to say that I noclipped at a few points because I fell into the void. Of course it wasn't until later that I would have just teleported back up. I felt dumb... I did get lost a few times, just trying to find my way of where to go next. Gameplay was tough but fair, though I did die from the gug at the end.
Newhouse - As others have said, its quite dark, but I assumed that's just the theme of the map, so I went with it. It didn't bother me too much, as I never really got lost. I died a really bizarre way at the end, a shambler just seemed to appear out of nowhere from behind and clobbered me.
Tens - That giant heart set piece was really neat, it gave me the impression I was at the very core of some intense secret underground facility, and I just discovered the truth of whatever had happened. Don't think I didn't notice that awesome owl statue hidden behind the cliff. Monster count was a bit short, a few more could have spiced things up. The map was over before I knew it.
A great effort by all involved! First run demos on hard skill, recorded in Quakespasm:
http://qrf.servequake.com/~orl/misc/orl_jam7.7z