Very cool idea! What happens after shooting everyone down? Is there a way to restart? It'd be fun if you started a new level, with increasing difficulty. Another idea might be a level without weapons, a sort of 3D Tron. :)
One thing that I'd comment is that movement seems to be limited, at some point you can't turn to one side/up/down anymore. You can then move to the opposite side really quickly, it's a bit weird. I think it'd be better to have unlimited movement (i.e. do loops).