In 2008, the German computer magazine c’t launched a competition to find the best program that could play Asteroids, the classic arcade game. It detailed the internals of the machine, and eventually chose from the entrants.
The winner, Helmut Buhler, was responsible for the video above. He realised that the random number generator at the core of the game was actually predictable, which means his code can fire shots before asteroids appear, or aim for both the asteroid and the smaller fragments that will spin off it.
If the sheer audacity of that doesn’t impress you, you may prefer the entry from Vladimir “Bleifuß” Panteleev, whose ship will scare the willies out of you as it slides at high speed just past vast rocks or the alien spaceship.
(Thanks to Paul Hammond for introducing me to these videos.)