The pixel art is great, and the music is good too. The gameplay itself is really simple,but that's not necessarily a bad thing. My biggest problem with the game was probably that the screen flashes a color whenever you or an enemy shoots. While it does give the shots some impact, you end up firing constantly so it's just continually flashing. I also imagine this could be problematic for people with Epilepsy. The sound design was goo, but after awhile the music just stopped for some reason. The gameplay itself is a bit too easy so the game doesn't ever end if you just hold down the fire button.
But overall, I had fun playing and the game has some good potential with a few tweaks.