Hi
Here is a userscript for downloading videos from GDC Vault for to watch them on a trip without internet.
When you visit a page with a GDC player it will a freindly button overlay. The resulting file will be in mp4.
Tested in Chrome for now.

https://greasyfork.org/ru/scripts/508497-gdc-vault-downloader

One still needs a subscription to the vault, correct? Your script just helps with downloads in a non-internet environment?

There are plenty of free talks from past years
Check for example this one : https://www.gdcvault.com/play/1024409/Creating-the-Art-of-ABZU