I personally spent close to 100 hours exploring the Capital Wasteland if Fallout 3, so seeing this guy do it in 23 minutes and 55 seconds is both impressive and a little sad, because he runs by so much cool stuff. I'm sure, however, to get good enough to do this he must have played the game in full several times.
This speedrun is from BubblesDelFuego, beating his own old record of 24:20. The run is what's known as an "any percentage" run, which means just getting to the end.
Of course it's not all done straight through, or in anything like the intended sequence. Bubbles makes liberal use of glitches that allow one to clip through walls and skip dialogue. And he just runs through combat.
But it still makes me want to play the game again. I think I'll take my time, though.
