For what it is, it's pretty decent. I have to admit that I played for a lot longer than I thought I would because of its addictive gameplay. I think there could be more though.
I feel as if I've seen this concept a couple time before, but it's a good concept so...¯\_(ツ)_/¯
The music and sound effects are also nice.
One of the major things this game lacks is a menu. There is not a pause button nor a mute button and there is a definite need for one. In addition to this, it would be great to have an options menu that presents some form of customization such as configurable controls (There are only two controls anyway though, so it doesn't really matter that much) or a "game color" changer. Also, perhaps you should add some modes and/or unlockables? I would love to see that!
Overall, it's a pretty neat game.