Killerball is, without a doubt, the most obscure game on this list. Released in 1991 for the Atari ST, Amiga, PC and Amstrad CPC it combined the hot Reagan-era passions for football and rollerskating in one violent, shitty-looking package. Five sprites dressed in head-to-toe American Gladiators regalia skate around a ring and begrudgingly take turns knocking each other over to steal the titular Killerball. It looks really, really bad. Killerball makes you respect just how difficult it is to build a complex network of rules to make a sport work, because if you don’t think it through, you end up with a roller-rink with a lot of Mad Max ennui and no fun.