Erase All Kittens is a free, open source game where students must change the code in order to rescue kittens. Arca is a tiny outcast creature whose only friends are the kittens. When all the kittens go missing, Arca sets out on a journey to find them, guided by a narrator who explains how to change the code. The player builds ledges, makes new portals, reveals enemies by changing the sky's color, and lots more. The site offers both a demo and a pilot version of the game.