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

Read dead redemption 1. A masterpiece.

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%.

Space Invaders

Asteroids

Pitfall

Might and Magic 3

F-19

Wow

Half-life

Dishonored

FF6, FF9 and Links Awakening

Max Payne. The original game was just amazing and the story was incredible.

For retro games my answer is probably Yoshi's Island. If you include modern games I'd likely go with Hollow Knight. If VNs count then Echo.

The Binding of Isaac.

This is the eternal game of ever. It is balanced, fair, excellent feedback (time to win), super I'm depth unlocks, one of the best meta games. Take the time to learn the basics and this game is infinite.

The end of the game blew my mind out of the water in a way no other twist has ever quite captured. It might have been the mental space I was in at the time too. Whatever the case, I will always remember the first time I played it.

I also wish I had played the first Golden Sun before the second, so if I could put a duology and that caveat in there? Definitely those two.

Star Control 2

I'm gonna say Skies of Arcadia, just love that game, and it saddens me to this day that Sega have abandoned it.

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.

Mother 3. I really don't know what else to say, this series impacted me so much in my youth and I wish I got to experience it raw.