Hold space and release to set velocity, press the up arrow to change ball. If you want to use it, just click "See Inside" and look for a comment in the background. And don't forget to give a credit :)
Just a ball physics engine test that I'm going to use on my upcoming awesome game. The engine detects the slope at collision and applies a normal force, friction and elastic force. Bounce sound effect was taken from https://www.freesound.org/ Code, design and art by me. Hope I helped :)