Love this game! Really awesome concept, turn on auto shoot (if your headphones don't break!), loads of fun, very creative idea with loads of potential.
Would have loved for the level itself to have been circular as well, movement would be so more intuitive this way. As a side note, possibly adding different enemies or guns would have made this super addictive. Better still making the centre of your fire change as levels progress, maybe the position of this could be drawn towards the direction that the players fire upon every missed shot. This would also encourage planning and reduce the amount of "spray and pray".
All in all, a very different submission that brought a smile to my face as I zapped cure, little, red cubes.