"What if Nintendo teamed up with Valve and recreated the famous Mario game with Portal gun mechanics?" That is the question the two-man studio Stabyourself.net decided to ask and answer. They completely recreated the original Super Mario Bros. from scratch, gave Mario a portal gun, and added puzzle game mechanics from Portal. That would have been cool on its own, but they didn't stop there — they added four-player co-op, a level editor, downloadable mappacks, and game modifiers, like super size. Oh, and keeping in true Valve fashion, they added 33 different hats. Have a look at the sweet teaser trailer:
Mari0 is available for Windows, Linux, and OSX. The source code is also available.