We're fortunate in that plenty of games are getting quality remasters, whether it's Crash Bandicoot, Spyro, the upcoming Resident Evil 2 remake, the work done on Shadow of the Colossus, and plenty more.
But sometimes the originals, even in 2018, still hold up real well.
The original Thief and System Shock 2 are two games I always think of whenever remasters come up, albeit for slightly different reasons. Thief's level design is still outstanding, even though the textures and lighting could definitely use a mod or three.
System Shock 2, on the other hand, has a visual style that is actually passable playing it back in 2018. There's some quirks and annoyances, like compatibility with widescreen resolutions. But on the whole, it works, it's perfectly playable, and the controls work well enough. The inventory system is definitely a byproduct of the late '90s, but you get used to that fairly quickly.
That said, a few texture upgrades certainly don't hurt:
Another game that holds up as well as ever is the Heroes of Might and Magic games, but specifically the second and third iterations. The original Complete Edition from GOG for Heroes 3 also has a wealth of cracking community mods to expand the campaign and races, but even if you're just playing through the original campaign content, you'll still get the full flavour of things. (Having the HD mod helps if you're running an ultrawide screen monitor and want a res closer to your monitor's native output, mind you.)
Cannon Fodder and Sensible Soccer hold up well today, although the latter really benefits the most from having a controller plugged in. I'm also a fan of the original GTA, even though getting it to actually run on Windows 10 is a right pain in the arse. The game plays superbly once you're past that hurdle, mind you.
What retro games do you go back to that still hold up well today?