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)
Is it just nostalgia because I had a GBC as a kid or is it because Game Boy games came later and had more developed visual aesthetics? 
My limit is probably the very late 80s
As a game, like mechanics and shit it's stellar, but every line of dialogue makes me want to punch every NPC. It's got slavery in it for no reason, and theless said about its "native" charicatures the better... Idk, I was really hyped to play it since Fallout was so good, people say this one is even better! Oh man! The one where you can have videogame secks on film!!
There's a bit where you can sleep with a farmer's daughter, get discovered by her dad and be forced to marry her. If your PC is female the dad will remark that the hawt lesbian action is turning him on
It's a really horny game
Absolutely Disgusting
The volcel police will be coming for every copy of this game.
Look on the bright side, it's probably one of the earliest depictions of gay marriage in a video game
It actually is which is pretty pathetic
نحن شرطة VolCel.بناءا على تعليمات الهيئة لترويج لألعاب الفيديو و النهي عن الجنس نرجوا الإبتعاد عن أي أفكار جنسية و الحفاظ على حيواناتكم المنويَّة حتى يوم الحساب. اتقوا الله، إنك لا تراه لكنه يراك.