I picked up Cotrio today as part of the bundle for Racial Justice and Equality, and I've played through around 80 levels non-stop. It is ridiculously addictive, and I don't even like puzzle games that much!

The game is atmospheric, attractive, and also challenging. Highly recommended.

My only negative observations is that the game seems more suited for tablet than desktop play — I couldn't operate the 3D environments with a mouse, and the help text talks about touch input. Also the progress bar suggests that the game stops at a certain level, but it doesn't seem to end! Beware!