Icy, a Twitch speedrunner, made it his mission two months ago to beat Portal without using a single portal. He succeeded, but it took him just under an hour to do it.
Two months later, the same speedrunner has nearly cut his time in half—he can currently finish the speedrun in less than 30 minutes.
Over the past two months, Icy has greatly optimized the route for the category and he's become a lot more consistent during crucial glitches.
Icy's most recent route allowed him to save over 20 minutes from the previous run that he published on Reddit two months ago.
The Portal speedrun isn't one of the most entertaining, but goes to show how well a speedrunner can perform after devoting so much time into a category.
The speedrun itself uses a lot of frame perfect glitches that many speedrunners thought only a computer could do—until now.