It feels very polished. Kinda wish controller was supported, but I have a hard time imagining how it's gonna go with the 360-aiming.
A very solid metroidvania, both mechanically and graphically. I didn't have that much trouble with the level design aside that one time when I fell down and kept falling due to disappearing floor - now that was dickish.
Noticed lots of stuff that's unlockable with grenades and tiny crawlspaces where I could slide before I could actually slide, which is nice.
I don't have much to say, honestly. It's great and it's very polished. Good stuff. Kinda unfair to other demos submitted due to how great this is.