Secret Maryo! Yes, the action of Mario's universe is recaptured in this 2D run and jump clone, which uses Simple Directmedia Layer under the hood to run. It's cool enough to play the maps provided, but Secret Maryo allows you to build your own wacky unlicensed fun as well. I'm not saying Secret Maryo is perfect, as it's at version .97, but it is progressing. As with all OSS, feel free to contribute bug fixes yourself, and join the developers in making this cool toy better. Even if you aren't a programmer, they're also looking for some level designers, so if you're looking to get in the game business, it's a great way to practice your craft.