I remember a few from various stages of my life (born 1984).
Seeing the demo footage of Sonic 2 in Woolworths and thinking the leaves falling down in Aquatic Ruin zone was so cool and advanced.
The original Sega arcade of Virtua Racing with the moving cars completely blew me away.
I remember my uncle loading up Cannon Fodder on his Amiga, and a REAL song with REAL music came out, along with REAL photos. I was amazed haha.
A few years on I remember a PlayStation demo disc having promo footage of the first Gran Turismo and it looked so real to me, I watched it over and over. The first Driver on PS1 looked absolutely amazing to me also.
Storming the beach for the first time in Medal of Honor: Allied Assault back in 2002.
Even though the graphics haven’t aged well (of course), the sound design, the vibration of the controller, the beats in the pacing as you are tossed around in the boat and then thrown overboard. It was all so well done. It was also the first time (that I could recall) where you began the game and had a moment to just “look around” while the boat was heading to the shore but before you had the ability to move.
You look behind you and you see other soldiers, some puking. Someone yells, and you look up as a fighter/bomber screams over you. The controller rumbles as it drops it’s load on the landing craft next to yours, tossing you around. The game took a few moments to let you immerse yourself in the situation before the action started, which I think was an amazing choice.
Anyway, that’s my answer. And yes, I’m old.