That's right, there is a solid 40 minutes cut off via tricks, shortcuts, and outright optimization. This is my second run through HL2 and it is better than my original in every conceivable way.
The in-game demo files are also available in a rar file, but require protocol version 7 to play. Demos were captured to AVI, appended into one file and compressed to one 320x240 and 640x480 version. Speed run of Half-Life 2 on normal difficultly in 68 segments.