Shooting seems ropey, they're spending a lot of effort trying to make shots connect, but the 360 aiming is in theory something good for the series so hopefully it's something to get used to. Feels like you need that knockback a lot.
Also the level traversal seems sort of off for some weird reason. (It looks like a linear game engine that got rejiggered to have interconnected tunnels, if that makes any sense?) Again, play might clear up that feeling.
I really like how expressive Samus is, how she strikes poses when shooting and swings her arm back when firing behind her and flips into her spin-jumps. Not a great character model, but it looks fine at a distance.
The Metroids looked weird on the feed (sort of blocky and ill-textured) but I think the transparency may look better on the 3DS screen because when you see a Metroid get sick, its texture evolved and the cracked-dry Metroid looked amazing.
...I want to like it. Not totally sold, something about it feels not-Nintendo'ish (which makes sense since MercurySteam is developing) but there's plenty to like in the long playthrough.