What is M.U.G.E.N.?
M.U.G.E.N. is a free 2D fighting engine created by the Electbyte team (dead now). It allows you to create and customize your own 2D fighting game. You can select the characters who will fight each other, set the stages of your fighting tournament, select the music that you want to be played, and so on.
All the elements required to make your own game are freely available on the Internet. The characters, stages and screenpacks that you will find are mostly converted from famous existing games such as The King of Fighters or Street Fighter Alpha. Since everything is free, these conversions are considered as "Fan Art" by the companies who own the rights of these games and thus are tolerated.
If you are a hard worker, you can convert yourself your favourite characters, stages and screenpacks from existing fighting games, and if you are really talented, you can even create everything from scratch. The process is awfully time consuming but seeing other people enjoying your work is one of the best awards you can get.
Whatever you decide to do, please respect the companies and the Mugen creators works ; do not distribute a work without the creator's approval (come on, after all the time he spent making it, let the people visit his own web page!) and if you see someone selling a M.U.G.E.N. game (on eBay for example), inform the webmaster that this person is breaking the copyright laws (people should not be paying for a free game!).
And now, enjoy your stay in the M.U.G.E.N. world! Yours.