Mari0 is a free jump 'n run side-scrolling 2D platform game developed by Maurice Guégan at Stabyourself.net and is a fan-made recreation of Nintendo's classic Super Mario Bros platform game series. The game is built from the ground-up and is designed to look and feel as close to the original game. Mari0 does have a unique twist, by combining some gameplay from Valve's Portal and giving Mario a portal gun and adding the puzzle game mechanics from Portal.
Mac OS X 10.4 or newer
Intel powered Mac
Free download at stabyourself.net