Press space to pause while in a game. The controls for player 1 are either the w/s keys or the mouse (you can change it in the settings). The controls for player 2 (only in multiplayer) are the up and down keys. AI difficulty from single player can be changed to your liking. You can control the amount of balls you want and the speed of the balls in the settings.
Online doesn't work because I haven't added it yet. The impossible level bot predicts where the ball will go so it is impossible to beat it on one ball. The level 12 bot is possible to beat on 1 ball and is easiest to beat when using a ball speed of 10. Using the mouse to control your ball is easier than using the w/s keys. Using the w/s keys requires more skill than using the mouse, so please don't use the mouse. (There is totally no instructions on how to activate an easter egg if you scroll all the way to the bottom of this.) There is a hidden function you can activate if you hold down p, e and n or c, a, and t at the same time...