This game is all about pushing a giant rock up to the top of the hill.  Hold the rock with SPACE key, and push it with -> key.  You have to press down both keys at the same time.  That’s all.  Nothing else.  Do not let your SPACE key up, the rock would kill you instantly.  Apart from your tragical death, there are multiple endings waiting for you to discover.  But we really don’t suggest you waste your precious time to do so.  Well, if you still want to know what lies on the top, good luck then. 4.22 update: Fixed something doesn’t really matter.