Asklemmy

I found an abandonware do of Risk 2 from 2000. Run great and is just as much fun as when I was a kid. A friend and I are going to try the network interface to play against each other.

Probably half life 2

Robotron 2084 - there is a place by me that still has the arcade cabinet.

I've been playing jet moto with my kid. Just like I did with my dad, back in 1996.

I still play a phone sudoku game from 2009. I would still play StarCraft and Warcraft 2 if I had hardware capable.

I replayed Vampire: The Masquerade — Bloodlines (2004) recently

Deus Ex 1. Still holds up after all these years and there are plenty of mods to keep things interesting.

1991's arcade hit and genre creating game, Street Fighter 2

Garrys Mod. You'd actually be impressed how many people still play that game for it approaching its 20 year anniversary.

Thief: Gold

The Dark Mod scratches that itch very well most of the time, but the OG had better story telling across multiple missions

River Raid, Atari game from early 80s. Play it on analogue pocket currently

DigDug on MAME

Portal. It's older than you think, but still solid.

Mario Kart: Double Dash!!

I recently picked up Diablo 2 again, that and Doom which I play off and on. I really need to find a copy of Wolfenstein now that I'm thinking about old games.

osu!. Despite being made in 2007, it still holds up as a good rhythm game.

About once a year or so I go replay Morrowind, the chaddest of the Elder Scrolls series.

This past year I replayed Morrowind with Tamriel Rebuilt tacked onto it, which has been extremely cool and fresh. TR really feels like official content a lot of the time, it's quite good and the love that's been put into it is very apparent.

Every so many years I fire up a King's Quest or Space Quest.

Mario 3, though these days I get tired of it after a World or two and haven't completed it in a while.

Also Xenogears from the PS1 is still one of my favorite games and I replay it every few years.

Freeciv

Anarchy Online (2001) is a game I play frequently.

Gothic 1 and 2 (from 2001 and 2002 respectively) are still some of the best games I ever played. There is also a very active modding community, and some mods are even much better than the original game.

I'm on a retro game kick lately. I am currently playing Pokemon Leaf Green and Chrono Trigger (for a fiesta event) and will likely move on to Castlevania: Symphony of the Night afterward.

Bejeweled 3 zen mode on my Xbox 360 till my Xbox one X

I play lots of games from my childhood. Even though it was before my time, Super Mario Bros on the NES is probably the oldest game I regularly go back to. But I love retro games, so I'll play even older games on occasion.

Started playing Spelunky HD again the other day, the sequel is better but the original is still fun to revisit.

Morrowind and Fallout: New Vegas sometimes. I've tried playing the original two Fallout games but I keep bouncing off the first hour or two.

Some Guilty Gear XX AC+R with a friend -- we would love to play some old Tekken games too but we're both on PC so Tekken 7 is the oldest available.

Every once in a while I'll play some Sacrifice, such an amazing game that's dying for a remaster.

The barcade near me has a Sinistar (1982) cabinet and I play it every time I go. I’m not even that good at it, but I love it so much.

Also I love those Lucasarts point and click adventure games. Grew up playing Monkey Island and play it again every once in a while.

Mario 64 on original hardware. Never did finish it as a kid so no time better than the present

I still play NES games often. These were the games of my childhood. Balloon Fight and the original arcade Mario Bros. are always fun for shorter sessions. And I still enjoy playing through Super Mario Bros. on occasion. I very rarely have ventured into games older than the NES.