Here’s a popular flash game: QWOP. It’s a game about controlling the leg muscles of a track runner on a 100 meter track. The ‘Q’ key rotates the thighs in a clockwise rotation, while ‘W’ rotates it counter-clockwise. Similarly, ‘O’ rotates the calves clockwise; and the ‘P’, counter-clockwise. This deliberately unwieldy controls, and the floppy rag-doll physics makes QWOP one of the most difficult games.
QWOP is playable at foddy.net.
Despite the difficulty, QWOP is strangely addicting. There’s a certain satisfaction when you learn to crawl to the first 5 meters, then learn the timing to hop to 10 meters. The simple music that plays as you start moving towards the finish line adds the gratification of moving forward. As the commenter below explains, slow and steady wins the race.