My strongest gaming memories are usually bittersweet. Moments in GTA: San Andreas and Vice City stand out to me. Also moments in Red Dead Redemption 1, but particularly when I replayed the game last year in anticipation of RDR2.
Playing San Andreas and RDR1 instantly bring me back to where I was, ~15 years ago with San Andreas and 10 years ago with RDR, when I was playing those games. It's usually a weird bittersweet nostalgia.
Like, sure I have a lot of great videogaming memories that are happy, but my strongest memories are the ones that make me nostalgic, and those are always tinged with a sad feeling of longing. Buzzing through the San Andreas dessert areas blasting KDST, 'Running Down a Dream,' or what have you, really hits me hard, because I'm transported back to Summer of ~2004 or 2005, doing that same thing, like flying from the Boneyard airport over Las Venturas and climbing over the Los Santos / Vinewood hills, with the classic rock station on.
There have also been moments in RDR2 that really hit me, particularly the end game and 2nd epilogue.
I also have other strong videogame memories, but they're sad. I remember the Oklahoma City Bombing terrorist attack because I was playing Sonic & Knuckles at the time, in the sand zone. I had a small TV that the Genesis was hooked up to, it was April vacation, and my sister was watching Price is Right on the TV that had cable, and it cut out to cover the bombing. I was 10 or 11, so I didn't care about the news, but I still remember it happening and strongly remember playing Sonic & Knuckles on that day.