I'm looking forward to this one, since I just finished the first ~a month ago. The graphics look fantastic, especially with the expanded color palette vs. Fall of Man. But I just got LittleBigPlanet and Rock Band 2 and I actually barely have any time for gaming in the next couple weeks. So I'll probably pick it up closer to Christmas-ish.
The no health-pills and 2-weapon limitation sound like they make the thing really different indeed. I kinda liked looking for the Sym-Bac (which I always called "healthy juice"), even though I wound up dying a lot (in Easy mode). It was fun to keep re-trying some hard part and having to plan your movements according to where you knew the juice was going to be..
Anyway, still looks exciting, and some of the new multiplayer modes look really awesome. Maybe I'll see you online when I pick this one up.