Very nice game! I liked the multitude of different things that can be done at once, never a dull moments. It might be cool to add some powerups that appear around the level (Better gun, bomb that destroys all humans on the planet, better speed, etc). Keep it up, I liked this entry a lot. 

Nice entry, I like that you put sfx and animation to almost all element. One comment though, I felt that there were to many elements to consider while playing it.