The game mechanics of Quadrilateral Cowboy (first published in 2016) are really innovative - I can't remember how many hours I lost during my first playthrough,

The game mechanics of Quadrilateral Cowboy (first published in 2016) are really innovative - I can't remember how many hours I lost during my first playthrough, but it was extremely engaging. It's available on a few different platforms, and the source code is available under a GPLv3 license.