Bounceball is a 2-4 player game that requires gamepads: in other words, controllers like ones used for the XBOX or Playstation.
It also requires a browser that can interpret the controller input. Chrome or Firefox is recommended.
If your controllers are not being detected, try the following:
Ok, good, so you've connected controllers. The game itself is fairly simple. 2-4 players face off in a game to the death, by shooting bullets at each other. Each time you get hit you lose 5% of your health, unless it hits your shield, in which case it will bounce off. If your player is flashing green, you can unleash a Big Shot.
The controls may vary by controller, but they should be relatively similar to the following, based on the XBOX 360 Controller:
If you want to hide this text, click the red triangle hanging off of the game view. Hiding this text and resizing the browser will also change the size of the game window.