I launched the steam version of portal to test an idea I had, but shortly closed it. I went to the Source Unpack to do some runs, but when I tried save glitching, it didn't work, so I checked the version, and and it said 5135 (Steampipe) although it should've said 4034 (i think so), i launched 3420 and it was on build 3420, but Source Unpack just went to the Steampipe.
source unpack is build 5135, you likely just did whatever saveglitch incorrectly. 4034 isn't a real build of portal.
It was recently discovered that it is possible to set your mouse sensitivity to a value so high that the game considers it infinite, leading to several new glitchy techniques being discovered.
The rules have now been amended to ban these new techniques in both Inbounds No SLA Legacy and Glitchless.