A "movement-simulator", I'm not sure if this type of game has a specific genre yet - but the core puzzle of Heavenly Bodies is figuring out how best to move individual limbs to push, pull, and swim your way around a 2D spaceship and carry out relatively intricate tasks. The fun of Heavenly Bodies is in the neat constant failure, and the utterly whimsical reality of the events on screen. It's fun on its own, but is excellent as a co-operative title.