I'm constantly in awe of the wild tricks that speedrunners discover in just about any game they set their collective minds to. It's always a treat to hear developers being equally astounded though, and Valve's developers are no exception. Three of them recently got to have a chat with Portal speedrunner "CantEven" to ask about extremely calculated trick shots, weird save glitches, and all the other things that game developers don't always know about their own games.
Getting developers to react to speedruns is a thing that IGN put together regularly, which is where this chat takes place. They've gotten together CantEven with Valve writer Erik Wolpaw, programmer Jeep Barnett, and programmer Garret Rickey.
In particular, CantEven explains one big trick that Portal speedrunners refer to as "save glitch". It's a method for breaking collision with walls by tricking the game into misunderstanding where you're actually standing. CantEven also explains how all of the portals he fires during his first speedrun appear to be quick, random firing but are actually extremely calculated moves.
"That is pretty much the most broken thing in both of these categories," CantEven says. "This is the thing that short papers have been written on. There have been probably multiple hundreds of thousands of words written about implications of the save loading."
Valve's developers follow along with the more technical side of the explanation, it sounds, better than I can. In all though, it does remind me of other speedrunning glitches I've seen performed that involve taking advantage of collision objects that aren't loaded while a player is far away from them.
Wolpaw speaks up with the realization that I think must be one a lot of developers experience when seeing the wild things that speedrunners do with their games. "We lived with Portal so intensely for so long," he says of the development process. "I imagine you had to play Portal as much as we did to get this good at doing the speedrunning. It's just strange to think of a second group of people coming in and living with it like that."
Certainly not all Portal speedrunners have been working with the same game since it launched 14 years ago. As a collective though, speedrunners over the years have certainly put their own massive total of hours into the game, just in a pretty different way than the developers would have.
Speedrunning continues to be fascinating. Here's a Half-Life: Alyx player crawling beneath levels in VR at SGDQ last year.