Its confusing as to how a sometimes fire a short range shot other times I don't even at full energy and ammo. I think the mechanics need better explanation, otherwise no point in continuing playing if I'm stuck in one level.
I finally made it past level 9 and completed the game. Still, the controls are often unresponsive, and the game feels way short compared to Zombotron. Its a nice idea, but it could've been better executed.