This game is a cockpunch. The control is somewhat clunky, the slowdown is equally horrendous (more than just a few "hiccups," at least from my perspective), and the flick targeting system - while a good idea - isn't so great in execution.
That said, I don't really care much for story. Outside of Card's penning, it's pretty much of the "Bad Aliens invade, you get powers, you're the ONE" type. I will agree that the game gets the alien invasion right, especially in regards to the carnage, and the powers you receive are equally nice.
Other than that, I'd say it's a good rental, but I'm not so sure I would buy it.