Mario vs Luigi by Chris Sumsky, Daniel Sabio, and Sam Rickles.

Release notes:

In this game, a two player battle between the Mario brothers for the love of Princess Peach, Mario (we mapped him to WASD movement and fire button ‘1’) and Luigi (we mapped him to the arrows for movement and fire button ‘space bar’) are controlled by humans with goal of traveling to the middle to pick up Princess Peach (by running into her) and then carrying her back to your starting point. Running into the other player will steal Peach, and shooting them with a fireball will send Peach back to the middle. Scoring resets the screen for a new skirmish on a new map, and 5 scores by a player wins the game! Space bar will reset from the win screen. Good luck and enjoy!

http://www.bogost.com/games/student_atari_games.shtml