You are the purple player. The others are blue. If you don't move for 2 seconds, you won't show on the other person's screen and there is a chance that you'll not come back. Non-mobile controls: WASD to move. Points toward mouse pointer. Space to shoot. You have 5 health. Mobile controls: Wherever you're pressing, it will move there and shoot as well.
Uses my infinite multiplayer code from a tutorial by @KRAZYKING1010 (this is his scratch username) Should I add more health? Use turbowarp: https://turbowarp.org/1305126896