Pretty competent all around but hard as nails.It's one of those games where I as a player feel kinda handicapped against super strong waves of enemies. Seems like power ups should last a bit longer. And the shooting sound is obnoxiously loud. Also, I don't really understand why the mouse is needed to shoot. Why not just use the space bar or something? Feels kinda awkward this way.
I also find the visual style pretty disjointed.

But these all really are just minor complaints. Overall it's very good and there really isn't anything substantial to moan about. It's just very easy to want to enjoy it just a little more.

A good all round game. Graphics look great, sound is good, and there is a decent variety of enemies. Great job. Well done.