Ich sag nur des is doch Kronk

The trick is that this is a tool-assisted speedrun — using emulators, save states, and running the games at a very slow pace, he was able to individually tweak and nudge each movement of the four Marios so that they would stay a hair’s breadth from danger. It’s still a remarkably impressive achievement when you consider the painstaking care that such a meticulous feat would require.

Via 

Portal done Pro oder der Weltrekord im Portal zocken

Der Junge hat über einen Zeitraum von 2 Jahren seine schnellsten Level zusammengeschnitten und hat nun ein kompletten Speedrun in 9,25 min geschafft. Hut ab. Das sagt er selbst dazu:

10 minutes. From when I get out of bed, to the time I drop the final personality core into the furnace, the time is 9:25.567. It is the current world record for Portal completion time.

Much of the speedrun is sitting in the elevator. I have not calculated yet how much time I waste waiting for the elevators, but I’m sure it is probably a majority of the time. I segmented the speedrun per map. This means when the game says, “Loading…”, it is loading a new map, and I save the game and load from there. The only exceptions are Chambers 02 and 13.

This speedrun uses a majority of the glitches in the game. Unfortunately, it does not use the acute angle glitch, which might be the most useful glitch in the game, if used correctly. All other glitches are explained in my series of commentary videos here: Portal Done Pro - Commentary Video