Battle Royale is the next big thing in video games as more and more developers add this kind of multiplayer to their games. Although some hate this new trend, we have to say that we were shocked when we learned that a fan created a freeware version of the classic NES version of Super Mario Bros on the PC that allows multiple players to play simultaneously, Mario Royale.
Mario Royale was created by "InfernoPlus" and is a complete remake of the classic Super Mario Bros game on PC, which works in any browser, can be played for free and is now available on its official website.  Now I'm not sure if Nintendo allows something like InfernoPlus, that basically the NES game is offered for free (even if it was recreated and a really cool concept behind it). For this reason, we strongly recommend playing it while it is still possible.
InfernoPlus spent three weeks creating Mario Royale, which is written in HTML5 using a Java server backend, and the game even has controller support.
In Mario Royale, players do not interact directly with each other, but they can break blocks, steal your power-ups, and attack you with Koopa shells.
Mario Royale sounds great and you can play it by visiting his official website here.  Have fun!