Perloo is a free app that has no 'help' page, no screen of instructions. It starts in black, and then a man in a meadow ruminates philosophically. The screen goes black again and you see a round white-and-black shape. It soon becomes obvious that the white shape responds to movement of your iPhone.
From there, I have no advice to give you. As you go deeper, the game gets more intensive and frustrating. Keep at it. There are worlds to discover and explore. I'm not sure how far I am into the game, and how far there is to go. That's one of the joys of how it all works.