[Fabian]

There are lots of videos of games beaten as quickly as possible in this manner on the site Grivan linked to. I've even done two games myself, so if anyone is curious about how the tools we use to make these videos work or something, feel free to ask me.

Short answer: There are no cheats or game genie codes or anything of that nature involved. Using built-in rerecording features in the emulators, the author has complete control over the controller input, meaning he can choose exactly which buttons to press on any given frame.

It's pretty fun to make one of these videos actually, trying hard to find the quickest way to finish a level and all that. Kinda like doing lots of challenging puzzles.