The original One Must Fall is a demo created in the wake of the success of Street Fighter II. It features two human fighters who greatly resemble Ryu and Ken as well as the Karate Champ fighters who fight in a single arena. Players can kick, punch, and throw their opponent; both players can also throw high and low fireballs, teleport, and do a special move jumpkick. The game was never commercially released, as it was considered too repetitive and slow, although on modern computers, the game will typically run many times faster than the original speed. (The game features a Speed option in one of its option menus to offset this problem.) This game was featured in several collections of shareware and freeware games. Source: Wikipedia, "One Must Fall", available under the CC-BY-SA License.