Use WASD or Arrow keys to move, Space or click to shoot, and 1 is Pistol and 2 is Machine Gun. The Pistol is for far-range because it is more accurate and the Machine Gun is for close-range because it has a burst fire, but the disadvantage is it is inaccurate and the bullets travel slower. The top buttons say which level you're in. You can change it by clicking on the button or pressing E, M, or H. Every 30 seconds, you gain all your hearts back. If you lose your hearts, You get infected and GAME OVER for you!
This is a very old project, but I deleted it. I decided to repost it cuz it brings back memories :)