It's gotta be DOOM! The first game to introduce me to PC Gaming outside of Minesweeper and Solitaire!
Gaming
I didn't play it on DOS, though it also saw a DOS release, but Syndicate would be high on my list.
Carmageddon was a late DOS release that I liked.
I never did actually get around to The Ancient Art of War, though I did want to play that.
I didn't play it on DOS, though it saw a DOS release, but the original Sim City aged pretty well.
Probably Lotus Racing (ran off one floppy), then Quake 1 and Carmageddon 1. Never really gamed much after those few.
Not to be the hispter, but my fav. is a very niche game called "Het Yogo Yogo Spel", it's a promotional game for a drink in the Netherlands. for some reason i have such strong nostalgic feelings for it, i really loved playing it as a kid and even more as an adult because it reminds me of that time so much. and no, it's not an amazing platformer (not bad either) but man...
Star Control II for sure. Fantastic game, still one of the best story-based games I've played. Heavily inspired a lot of more modern franchises, too, including Mass Effect.
I got into ZZT, a "topdown" 2d game with its own map editor and even a rudimentary scripting language. Stumbled on it because I wanted to make games. People made some seriously impressive shit on that thing and its successors.
Heroes of Might and Magic II, I still will fire it up to play occasionally! I have so many fond memories of me and my dad playing into the long hours of the night.
Theme Park. So classic.
Star Command was my favorite. Loved recruiting crew members, buying and upgrading ships, and going around the galaxy to complete missions. It's the game that got me hooked on RPGs as a kid
Sid Meier's covert action. Absolutely amazing spy game with lots of minigames and a randomly generated hierarchy of bad guys to catch every mission. Really want a remaster but I don't think I'm getting one.
I never had a DOS computer back then and only played a few games through emulators in recent years. It has to be DOOM for me.
Hard to say. Secret Agent, Treasure Mountain, Azrael's Tear, Chill Manor, etc. All solid games. Hard to pick just one.
Supaplex and Gorillas are my go tos!
Gunship 2000. Shit was amazing.
Ultima series.
Probably X-Com: UFO Defense. Got really into it and holy hell got angry at that game. But damn it made me want to play more!
Doom, Duke Nukem 3d, Zak McKraken and the alien mindbenders, One Must Fall 2097
Crusader: No Remorse/No Regret
Sometimes I wish they made an FPS reboot, then I remember EA owns it.
Wolfenstein 3D, my first ever PC game
my dad gave me a floppy disk from one of his coworkers with instructions on how to navigate and run the game from DOS and I felt like a hacker lol
Every once on a while i get back to Mad TV. Casual game before it was cool. Also Indiana Jones: Fate of Atlantis