M.U.G.E.N (also known simply as MUGEN) is a freeware 2D fighting game engine designed by Elecbyte, written in C which originally used the Allegro library.
http://en.wikipedia.org/wiki/M.U.G.E.N
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M.U.G.E.N, free download. M.U.G.E.N RC7: Create your own 2D fighting games. Chances are, you've probably played on several games created by the M.U.G.E.N
http://mugen.en.softonic.com/
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The world of MUGEN, chars, stages and addons
Offers news, characters, forums, and game information.
http://www.mugenation.com/
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Master Shake vs The Transformers [M.U.G.E.N]