The Tragic Boundabout, a free fully customizable platform game for Linux has just been released here on itch.io It is fast, springy, silly and colorful.
If you don't like the level designs, you can design your own, as well as modifying the game by using your own graphics and sounds. Full details of how to do this, as well as easy installation instructions and details of the controls are included in the README file supplied with the game.
It's free, so give it a go if you want a fast scrolling platform game that is strange, and a fun challenge. And please let me know if you have suggestions for improvement or anything else to say, I would be happy for your help in making something better.