Sketch Nation Studio isn't really a game, per se. It's more like a mini game studio that you can fit in your pocket. It gives you the tools to create very simple mobile games. Skip Apple's grueling process of getting your game approved. Make some silly levels using this app instead. You can even host your creation as a stand alone game to share a profit with developers Engineous Games Inc.
Designing characters and levels is as easy as choosing from an art gallery, or hand-drawing your own designs in-app. If you're more comfortable with pencil and paper, you can import that drawing into the game by snapping a quick picture of it. Sketch Nation Studio lets you create jumping platformer games like Doodle Jump, flying games similar to Jet Pack Joyride, side running games, and others. If you're feeling like a real professional, you can even opt to tweak more advanced facets of the game in Advanced Mode.
Sketch Nation Studio [Free, iTunes]