Quite simple in its graphics and its gameplay, yet quite entertaining.
There isn't a lot of feedback to your actions, and I didn't quite feel in control. The player sort of just shot without me, and sometimes he shot in many different directions. My only job was moving my mouse, thus avoiding small light-blue orbs on the screen. If there were some screenshake when the player takes damage or a small explosion when an enemy was killed, it would dramatically improve the look of the game.
All in all a decently fun experience with very simple gameplay and graphics :)