The Legend of Zelda: Four Swords Adventures
Hey kids, remember Game Boy connectivity? Don't tell us you never grabbed three friends with three GBAs and three link cables for a rousing game of The Legend of Zelda: Four Swords Adventures. Because if you didn't, you've never really played the game.
Above: Four people running wild, each with their own screen
It's possible to run this one solo, controlling all four versions of Link, but multiplayer opens up an entirely new avenue of rivalry. You're all free to roam around, entering houses, caves or whatever else you want, all while looking at your own private GBA screen. To anyone else watching, it's an indecipherable mess on the main TV, with little Links running all over the place in a quest to earn the most Force Gems. You can pick up other players and hurl them into the abyss if they get too close, or steal precious weapons before they get a chance to grab 'em.
True, this slightly falls into that Steel Battalion territory, but you don't have to play this with four people, and the likelihood that you had three available friends (who also owned GBAs and link cables) with time on their hands is pretty slim. Fact is, this is an underappreciated game, quietly released in the summer of 2004 - grab it now and start making enemies out of your friends.