Use arrows keys to move. Space to shoot. 1, 2, 3, 4, 5, 6 to change weapons. Z, X, C, V: assists. Use the knife to run, holding a gun will slow you down. The different assist buttons (c,x,c,v) all do different assists, each one has its special uses. All bosses have a pattern. Watch out for your own grenades, they can kill you too. Hold down and shoot in the air to shoot downwards. Crouches reduces your chances of getting hit. Picking up a weapon automatically switches your primary gun.