Secret Maryo Chronicles – Open source clone edition of SMB series

Secret Maryo Chronicles (short for SMC) is an open-source, cross-platform 2D side-scrolling Mario clone game, which was inspired by the famous Nintendo Super Mario Bros. series (especially the Super Mario World). It's written in C++ and based on OpenGL, supports Windows, Mac OS X, Linux (Unix) and many other platforms (can be easily ported).