My first dedicated gaming system was the PS1, and in general I have no trouble going back to the sprites and chunky polygons of the mid-to-late 90s, whether on consoles or computers
spoiler
as long as I can upscale them to 1080P
Beyond that it gets a bit hit and miss- SNES and Mega Drive games look and sound fine to me and I've played plenty of 16 bit console games as an adult. On PC, I can enjoy 2D stuff like Sam & Max Hit the Road or the original X-Com but most early 3D, like the original System Shock, looks a bit too much like visual vomit.
Going to 8-bit, while the vast majority of NES games are too primitive to my eyes and ears, I have no problems with Game Boy/Game Boy Color games.
spoiler
(Well, at least the good ones, mostly made by Nintendo)
My limit is probably the very late 80s
While I'm not hugely into NES games I can see their appeal aesthetically and they mostly still read as "video games" to me. Anything Atari starts to look a bit too rudimentary to my 90s eyes
Its kinda the reason why I want to sit down and give some honest effort to play through some of the Atari XX00 console games someday. Kinda like going to a "hands on" history museum.