Very nice.
I don't typically get into shooters but this one is pretty damned nice. Pretty balanced with the difficulty, and I like how it employs more strategic thinking than simply equipping the strongest weapon and moving around while holding the Fire button down; you actually have to memorize when certain waves of enemies come from what direction, and adjust the direction of your weapons and the type of weapons you use accordingly. Only one I didn't quite understand was the point of the Ghost Cannon when it's only faster by a tiny margin. But yeah, otherwise I love the game.