I stumbled on a great game the other day called Eversion. At first this game seems to be a simple, cutesy platformer, but it holds a great twist that starts simple and gets weirder and weirder.
I really don’t want to give anything away, so I just recommend that you give it a try. A bit of advice should be helpful though, the spacebar does something, but only in certain locations.
I wish you the best of luck as Eversion is not an easy platformer.