Different games affected me differently, when I was 13 I could play Goldeneye 4 player on the N64 for hours with my friends but the Turok multiplayer focused game I could only handle 30mins before I would get nausea. I grew up playing Doom and Quake on PC without issues. Some games still make me sick, Dark souls 1 I have no issues with but Dark souls 2 is unplayable for me. Also I can play Rocket League for hours and feel perfectly fine. The source engine in VR was the worst experience for me and now when ever I see half life 2 in motion it makes me sick.

It’s quite varied and I would like to figure out what the common denominator in all of this that triggers my nausea response.

I am one of those people! I got over it once during the Doom era, then a second time during the Counterstrike era. I keep trying to get used to it a third time but it hasn't worked.

I don't know whether the games changed rendering in some way, or my monitor is too big, or it's just age.

I couldn't play Wolfenstein without getting nauseous, but for some reason doom was fine. I think ut is ok to release a video game that some people can't enjoy. We don't forbid flashing lights, and that can send some people into actual seizures!

I still get motion sick after a while when watching someone else play an FPS. If I'm playing myself there is no problem. I can also get motion sick as a passenger in a car, but have no issue driving.

This is still a thing. My partner can't play Skyrim in first-person mode, only in third-person mode, because of motion sickness.

Doom on SNES was instant motion sickness for me. Thankfully I only rented it from blockbuster!