Valve stiffed speedrunners by adding an invisible wall in its Half-Life 2 tuneup, so now it's fixed the fix and says 'enjoy'

pcgamer.com:

The 20th anniversary of Half-Life 2 saw Valve release a major surprise update for the PC gaming hall-of-famer (as well as an excellent two hour documentary). It integrated Episodes 1 and 2 with the base game (so you can now play through the entire experience seamlessly), added a new commentary track from the old gang, and for the coup de grace every location was given a glow-up: «Every map in Half-Life 2 has been looked over by Valve level designers to fix longstanding bugs, restore content and features lost to time, and improve the quality of a few things like lightmap resolution and fog.»

Lovely! Except perhaps if you're a Half-Life 2 speedrunner, one of those freewheeling souls who's long ago stopped seeing the G-Man and looks at City 17 like the Matrix, pinballing the Freeman from checkpoint to checkpoint on Valve's hidden flippers. It turns out that, when improving everything, Valve's current designers added an invisible wall to a large sewer pipe. And speedrunners promptly started slamming right into it.

The map in question is Route Kanal or «d1_canals_03» and features a puzzle where the player has to turn a valve and flood the pipe in question in order to pass through. The upper section of the pipe is supposed to have an invisible wall to stop the player getting through before they've solved the puzzle but, for whatever reason, this has only ever been present in the Xbox 360 version of the game, and thus taking advantage of the missing wall (by glitching up the surface with physics objects rather than adding water) is a regular part of PC speedruns.

The Sourceruns wiki keeps detailed notes on the differences between various versions of Half-Life 2 and now has a section devoted to the 20th anniversary update with various grumbles. Here it notes that «the pipe near the end of the level has been blocked off by a invisible brush which was previously only present in the Xbox 360 version of the game. The brush disappears once the player solves the puzzle in the