A little repetitive...
... but that's not always a bad thing. Tetris is repetitive. I wouldn't put this in the 'timeless games everyone is going to be playing forever' category, but it's a solid little timewaster.
It's similar in gameplay and design to other games of the same genre, which I like - if a system isn't broken, and is still enjoyable, there's no real need to innovate. That being said, the only thing that really sets this apart from the legion of other fixed-point casual shooters is the Rambo styling of the characters (love that movie, so, points, man).
Overall, controls are good, sound is good, Hambo is adorably badass. The lack of anything new takes away from the score, but this is a solid game no matter which was you cut it.