Researchers trained a deep learning network on photos to make GTA5 more realistic-looking: https://www.youtube.com/watch?v=P1IcaBn3ej0

I was surprised that most of it is is just tone mapping. It looks too green-ish to me, needing some white balancing, but realistic.

I think Video games are intentionally over-saturated and contrasty to make them look better, just as paintings are[1]. I took many screenshots in Horizon Zero Dawn that would be look bland if it was realistic like the modfified GTA5 footage above[2]. You also don't want animation movies[3] with realistic tone mapping. But for a horror game you would do exactly that, it's about immersion (or you would never be frightened), not beauty.

[1] https://www.reddit.com/r/horizon/comments/1ix7ms2/my_hzd_oil...

[2] https://www.reddit.com/r/horizon/comments/x97gi1/this_game_i...

[3] https://www.imdb.com/de/title/tt0892769/mediaviewer/rm284102...