Probably one of the machines at a nearby arcade. Pin-bot is mid-80s and I play that one a lot. There's a couple from closer to the 50s as well.

Amiga Stunt Car Racer remains the best racing game of all time for me. It even had linkup multiplayer (I think..)

I was playing Bubble Bobble on an NES emulator, so… 1988

Trying to finish pokemon emerald on my game boy micro. I mostly play at family gatherings

Oldest I have played during this year? Or oldest I have played up until this year?

Moon Patrol on the Atari 2600 (Emulated on my Steam Deck). I'm not giving away my age by posting this at all...

Played with various ROMs of popular late ‘70s and early ‘80s arcade games.

I played through Wario Land on GB emulator earlier this year. Probably that.

The London Game, from 1972.

I played the similar game Stunt Driver on PC a lot growing up. Had a tweaked copy where all the stats were turned way up on one car. Good choice to play as an old game

Galaxy 5000 (1991). Not the oldest in this thread by far, but I've never heard anyone talk about it and it's actually a really decent racing game for its time.

I've got Pong on my phone and one of my kids loves it.

Oldest game I’ve this year: https://wikipedia.org/wiki/Astro_Warrior
on Steam Deck

I’m a bit bummed the question wasn’t about the oldest game I’ve ever played (as I misread it at first), but that would be:

Golvellius on the Sega Master System.

I've owned it since the 80s but back then couldn't get very far. The fact that it uses passcodes instead of saves didn't help. Last month I played with a mod which adds save support, on the MiSTer FPGA (which I have installed in a C64 shell), on a nice ~10inch OLED.

I got all the way to the final boss but... still haven't beat it.