I am a fan of time attack movies. For those not familiar with time attacks, they are videos of speed runs through various video games. An important thing to note is that an actual human is not playing these games. They are carefully executed frame-by-frame to (hopefully) complete the game as fast as is technically possible. If this interests you, check out this site.
You can grab AVIs of the time attacks, but the way time attacks are distributed in the purest form is with an emulator movie file. This file contains all the information about which buttons were pressed at which moments for the entire run through the game. Then, if you wanted to watch it you could plug it in to an emulator with the game ROM and watch it played via those button presses.
Now, I am building up to talking about a very specific time attack video I watched last night. Somebody managed to create an emulator movie file (series of button presses) that works for two different games, Mega Man X and Mega Man X2. In case that didn’t sink in, that means that the exact same controller input will complete two different games from start to finish. In fact, when you watch the AVI of it, you see both games played through side-by-side. You see both Mega Men jump and shoot at the same time, but in two completely different situations. How the author (DeHackEd) did this I may never understand.
I suggest you download and watch the greatest time attack ever conceived (as of July 17, 2005).
I saw it and it was jawsome.