Original yet simple, and a very great game
It's rare that we see such an original game, that still manages to stay simple and fun.
There are only two points I have to whine about :P
the first is that the final ennemy was, well, weird. I understand that the core of this "universe eater" or whatever it was would attack me, that made sense. What didn't make sense was, well, how the hell do I kill him. I mean, I won, but I still have no idea how I did it!
The other thing that was a bit annoying was the lack of a tutorial. I still don't really know what the different shots really did, and had to figure out what the powerups do (and that there are powerups) on my own.