It is impossible to separate it from the time context and age, a lot of these old games will not spark now. But in now particular order:
- Elite: it had almost no graphics, but boy, what did it do to my imagination...
- Starcraft: there were good RTS before (Dune, C&C), but this one nalied the design and an epic story.
- Wing commander 4: A bit late to the party, so laid my hands on this one. Space opera meets movie, overall great.
- Planescape Tourment: One of the weirdest, if not the weirdest RPG with a sad world and once in a while really interesting NPC and story. Also bonus points for not using a high fantasy setting. Tops BG in my opinion.
- Fallout 1&2: Loved it for atmosphere, humor and tactical gameplay.
- Jagged Alliance 2: Trashy tactics, very fun.
- X-Com: (the remake and sequel): They've nailed the gameplay and imo the remakes are better than originals which were all over the place.
- Bloodborne: My first soul, came for suffering, but stayed for the lovecraftian horror.
- Street Fighter: The foundation for my love to the genre after all the years, and also the best thing to play with friends.
- Elden ring: A very recent one, but I was impressed with a sad, quiet world and a long forgotten feeling of exploration - you want to know what is behind the next corner. Open world done right.
- Last of Us: The most atmospheric game I've ever played. A work of art. Stay away from the sequel.
- GTA 3: I was completely stunned at the moment it came out. A sandbox world where you could do whatever you wanted? How did they came up with it? The magic wore off long time age, I actively avoid most open world games these days, but I remember the feelings.
I guess I could remember much more, since I do gaming for 30 years already, there is Privateer, Monkey Island, Half Life, Deus Ex, Prey, Dirt/2.0, but these were the most memorable, I guess.