Like you said, it is a pretty short game. But don't let the shortness deter you guys from playing it. The animation is brilliant. The explosions are pretty... explosive. It's a good thing you added an option to tone it down. It was starting to hurt my eyes.
The controls were very fluid. So I honest to god, appreciated that. But what I loved most was probably the music itself. Who did the soundtrack? If possible you should put up the credits for the music, and/or have a link to where I can get the sounds for it.
All and all, it was a very good game. Keep it up, maybe for the next sequel have a storyline or increasing difficult waves of enemies.