10. Portal
https://www.youtube.com/watch?v=W1U5RUVENNE Starting out with something fairly modern, this speedrun of Portal - the brain-bending game from the same developers that brought you Half Life - is mighty impressive. Physics-based puzzles may not seem like the most obvious hook for a videogame, but Valve somehow made it incredibly fun. The sense of achievement when finishing the game after a matter of hours is tremendous, but doing so in less than 10 minutes takes some serious, serious skill. If only that Portal gun were real...