Let’s just count ourselves lucky that this game didn’t have better graphics and a requirement to use the oculus rift.
The Strogg transformation scene is one of the first in the game and it involves watching the main character go through a brutal surgery in which limbs are cut off, the chest is cut by saw blades and the head is drilled from the main character’s perspective.
If it weren’t for the low-fidelity graphics of Quake 4 this scene would be unbearable, nevertheless, this cinematic disturbed many people.