This will be the Blue Bomber vs. Robot Santa Claus, the psychopathic mechanoid of the Futurama universe.
Round I) Mega Man (game universe) vs. Robot Santa, Mega Man has only closest equivalent weapons to any and all gear that Robot Santa has been seen using in the Futurama universe.
Round II) Same as Round I, but Mega Man can use the Double Gear System.
Round III) Same as Round I, but Game Mega Man is replaced with Ruby-Spears Mega Man, with all of the weapons he has ever used in that cartoon.
Round IV) Mega Man X takes on Robot Santa, X gets all equivalent Maverick Weapons in relation to any and all gear that Robot Santa uses.