The Vampire patient is probably the only hardest part in the game. At the end, how can you cut off the vampire's head for? If cutting head, then the vampire is killed. This really confuses me.
For those who likes auto-fire, here's how it works. First, during the gameplay, hold down your mouse button to fire. While holding down the button, move your cursor out of the game window and let go off the button. Then move your mouse cursor to the game and don't press the button, and you'll get auto-fire. If auto-fire stops, repeat the steps.