Hunt or Run by Adrian Laubisch is a 2D platformer arena multiplayer-only NES prototype. The idea behind it is that each player has a role that flip between them over time and time again. The players must concentrate on “What do we do now? Hunt or Run?”, because if not, they can get themselves killed quickly! Basically two players must kill each other by hitting he/she with a ball. But there is only one ball available! And you only can touch the ball on your turn, otherwise you are dead!

http://globalgamejam.org/2015/games/hunt-or-run