Hot Blood Boxing
Box against the computer or a friend on one keyboard -- ragdoll physics, knockdowns and a crowd that roars, in one of the flash era's most-played two-player fighters. Andy Law's build for CrazyMonkeyGames counted three million players by the start of 2009, and it was everywhere portals carried flash: two gloves, a health bar each, and the whole match decided by who lands the heavier fist first. Player one keys around WASD with G and H for the fists, player two joins on the arrows.