Players play as an athlete named QWOP Unblocked, who is participating in a 100-meter event at the Olympic Games. Using only the Q, W, O and P keys, players must control the movement of the athlete's legs to make the character move forward while trying to avoid falling over. The Q and W keys each drive one of the runner's thighs, while the O and P keys work the runner's calves. The Q key drives the runner's right thigh forward and left thigh backward, and the W key also affects the thighs and does the opposite. The O and P keys work in the same way as the Q and W keys, but with the runner's calves. The actual amount of movement of a joint is affected by the resistance due to forces from gravity and inertia placed upon it.
Though the objective of QWOP is simple, the game, ever since it was released, has been notorious for being difficult to master due to its controls with the Q, W, O and P keys. Foddy says that he gets a lot of hate mail for making QWOP. Despite the criticism for the game's difficulty due to the controls, the game helped Foddy's site reach 30 million hits, according to Wired Magazine, and, also ever since the game was released, has been played by millions of people, although numbers have declined.