Grandia on ps1. I refuse to replay it out of a morbid certainty that it's basic as all hell. But it was my first jrpg and it blew my mind.

I swear it took me weeks to make it to the wall, but searching my memory it's the first scene after your hometown.

Homeworld

Half-Life 2 and Shining in the Darkness.

Are you aware of the Zelda: ALLTTP randomizer? https://alttpr.com/en

I agree with lots of what's already been said and haven't got much to add to those extant conversations, so let me try to add in some that I've not seen:

RuneScape is a candidate. I started way back with RS Classic (the sprite-based one!).

Oh, and Dwarf Fortress too. That began in 2009.

Achaea and/or Lusternia are way up there but I don't imagine anyone but me can share the experience.

Oh, as well, Mount & Blade: Warband. Quite the adventure(s).

I don't really game anymore. But this thread did dredge up some memories, old and new.

Thank you.

FF6, FF9 and Links Awakening

Might and Magic 3

F-19

Wow

Half-life

Dishonored

Learning Team Fortress 2 for the first time as a teenager was such a crazy fun experience.

Chrono Trigger, Castlevania SOTN, Pokemon BW and B2W2, Dead Cells

The return of the Obra Dinn. Really fun unique game

I feel its been so long since i last played it might feel new to me, but still it wont be the same as first playthrough.

Skyrim. After 200 hours, you start becoming really aware of the "seams" and the clunkiness of the Creation Engine. Although, while you're still working your way through the quests, and every stat isn't at 100 yet, it's pure pure pure bliss. To have that original feeling back. Gah!

That'd have to be Metroid: Zero Mission and The Legend of Zelda: Wind Waker. Two of some of the only games I actually 100%.

Breath of the Wild or Tears of the Kingdom. BOTW was my first Zelda game and I honestly loved it. I would sit for hours in the living room zoned in to the game with checklist paper and notebooks next to me to keep track of what I was doing. If I could do it again I'd instead use an interactive map like I did with TOTK.

As for TOTK, the Rito dungeon was my favorite and if I could experience that adrenaline pumping battle for the first time again, I would. Tulin is a baby and I love him.

If I were to experience it as I am today (and judge it versus games with modern graphics etc), I'd pick Ori and the Will of the Wisps. It quickly became one of my all-time favourite games, and I finished it three times in a year when I discovered it. Beautiful in so many ways.

Half-Life is probably the game that has had the biggest impact on me, though, so that would be my pick if I experienced it as I did around 1998.

Wings for Amiga, flying in WW1 and a cool story between missions. Everything I know about ww1 air battles, I know from that game :)

Nier Automata

A game I will never forget

Quake 3 Arena. Or more specifically OpenArena + baseq3 and other mods like ratmod. Most fun I have had playing a game ever.

I have seen no mention of Planescape Torment, so there you go.

Probably Fallout New Vegas (if that even counts as retro yet). I've played it to death ever since it came out and can't even remember the first time I completed it.

Silent Hill 2

I've replayed that game so many times but the first playthrough hits different

Spyro the Dragon as I was back in the day. That game has always been so magical for me.

Hotel Dusk.

Read dead redemption 1. A masterpiece.

I know this is almost a stereotypical answer, but the Witcher 3. because after that game i went and read through all the books. so if i got to re experience it would be the difference of finding siri after 100 hours of gameplay and finding siri after 5000 hours of story. "find siri' is Geralt's primary motivation throughout the books. i can only imagine how satisfying and emotional that scene would feel for the first time with the weight of the books behind it.

Ghost Trick: Phantom Detective

The story has so many great twists and turns even up to the very end. There was a distinct point about 75% of the way through when I came to the realization that I had to binge the rest of game. Even if it meant I got zero sleep that night, I had to see how it ended.

It was so good I wish I could experience it again blind.

Bioshock. I am sure you can just replay it. The twist at the end... I wish I could relive the surprise again.