Well, technically that falling dude's butt (literally his butt) is controlled by little ball, jumping in 2d environment and having nothing in his little world except of static walls. Ball's position is controlled by mouse or touchscreen, but I messed up with keyboard controls (kbd controls speed, not position). Unfortunately I was quite short on time to fix it :(
You are second person mentioning Super Auto Pets - but I didn't even hear about that game before, actually. I got the music on Unity Asset Store