So, that footage features making of a brick wall texture in Softimage XSI.
I found that footage here:
https://valvearchive.com/archive/Half-Life/Half-Life%202/Videos/and when they fired up the game...
the game was the same as the leaked beta.
Differences:
Earlier Menu background
Minimize button on Titlebar. A few months later, the minimize button got removed
Different icon on titlebar (?)
HUD Number Font. It was Arial instead of DIN-Regular, probably because the hud was unfinished
There is no FLASHLIGHT ON/FLASHLIGHT OFF in the HUD.