Centered on the mechanic of changing your color to interact with different objects, Coloraze, a puzzle platformer by Colin Brown, is a simple concept done well. It's one of those works where a string of gameplay elements are introduced in the beginning, then paid off in the long run with a string puzzles that force them to interact in interesting way. Each individual level won't take too much time to play, but with a good ninety included, plus a solid number of levels made by the community using Coloraze's solid level editor, you won't be running out of game any time soon.