The new L3 screenshot is very very nice. I think you should recreate your previous levels becuase the new screen puts them to shame ;p
Played the demo. First level was really fun but really needed some music. It was also quite bleak but i understand why because it was quite a large level. But i think you should pack more meat into the opening room, because it didn't look much of a freezer to me.
2nd level gave me a bit of trouble. I randomly spawned 1 floor up at one point. The difficulty increased tenfold aswell. Just coming from a great run and gun level into that put me off a bit. Perhaps increase the difficulty more gradually.
Also, the most effective weapon there was a handgun :p 2 shot kills. The rifle wasn't as effective, and the MP5 or w/e was pretty much the exact same.

Spartans! Ready your breakfast and eat hearty... For tonight, we dine in Hell!