It's hard to tell if the climb/slide/etc. button is a gimmick or a legitimate feature. Gonna have to wait for more videos to decide. At the moment it looks kinda like a bargain bin game, but if the climbing mechanic is actually well-done, it'll definitely jump up my list of games to buy.
As far as the look, I'm not too sure how I feel about the toon-ish characters. It reminds me of Borderlands, which had comedy to go along with it, which made it worthwhile. If this game does something along those lines, I'll be satisfied.
Side note: It's kinda disappointing that a shotgun shot from 2 feet away only causes an enemy to fall to the ground (with a poor animation to go along with it).
Unfortunately, the levels look just like Killzone 2's levels, which means the graphical differences are going to stand out like a sore thumb. It looks absolutely fantastic considering it's multiplatform, though (and running on the Doom friggin 3 engine!).