The absolute best 800 XBL points you could possibly spend.
I immediately bought the full version and loaded it up. I was blown away.
Gameplay: Excellent. Here's the layout. A= jump, (x2) Double jump B=punch, X= pick up guns, grab, Y= Dash, R trig= fire primary function, L trig= fire secondary function.
Each weapon has two functions, and there are a very large variety of excellent weapons that are as fun and creative as can be. The controls work perfectly for the intense fast-paced gameplay.
Graphics= No lie, these graphics are amazing. This is the best XBLA game yet graphics wise and gameplay wise. The graphics can even compare to some actual XB360 games!
Sound= Constantly buzzing. Gun fire lights up your speakers, and if there are background sounds, you wouldn't know it, and that's kind of, Eh.
Multiplayer= Excellent. No lag, just like playing the computer, except that you know that you're blowing up an actual person.
Overall= The game is great, Buy or die, people!