>>725348923
The gate is based on og STALKER concept art, putting Gordon Freeman in SOC isn't much better.

GSC itself left put non-licensed songs in game files, which is as bad SOC helicopter here
https://www.youtube.com/watch?v=I5mStLWXnKc

And they used assets ripped from other games, like Quake 3 or Serious Sam, during the development.