Use your mouse to aim, and click to shoot. Press "R", to reload and press "Q" for Quality. On each level there is a time limite. When the time runs out, you go to the next level. There will be health in your inventory, press the Space bar to use them if your health is runing low. There will be heath 2 heath packs you can find in the game behind something or someone. And when you run out of heatth, the game is over.