Because ?Super Mario Bros.? from the Nintendo Entertainment System is a copyrighted game, fans cannot play it online for free. However, fan-created games that use classic Mario art allow gamers to play online for free on websites such as TheMarioGames.com.
Although most fan-created Super Mario Bros.-themed games star Mario and his brother Luigi, some games incorporate other iconic gaming heroes from the classic title. An example of this is ?Metal Slug Mario World,? a game in which players control the hero from the "Metal Slug" universe but battle enemies found in Mario games. Most of these fan-created games are also free to play and don't require players to download anything.