A really simple game I've put together with the style of an old Atari game. The instructions are, if self-explanatory, put here. Red guys = zombies. You touch, you die. Blue guy = friendly soldier. He will try to help you. He respawns every 5 seconds or so. Green guy = you. The player. Control with the arrow keys. Press space to fire a bullet. Blue guy can do it, too.
One last thing- you shoot in whatever direction you last pressed on the arrow keys. If you last pressed up, expect to shoot up, etc.