This will get pretty confusing for any player... We have to confess that we really didn't understand what to do in this game. You are an alien on a hoverboard that can shoot.
You are trapped in a large square room (arena?) and various coloured balls home in on you. If too many of them hit, you die. You can also shoot them, but we're not sure why you'd want to (i.e. there is no clear objective to this game).
We thought at first that maybe you collect the green balls and shoot the greys, but that didn't seem to do anything much and we ended up losing the game repeatedly.