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.
The moment when you see the first colossus in Shadow of the Colossus. You’ve watched a contemplative intro movie that sets the stage, been faced with a desolate land that you’re seemingly completely alone in, and charged headlong with only the light shining off your sword to guide you. You’ve seen nothing but you and your horse moving in this place in the half hour or so you’ve been playing so far. You’ve done just enough platforming to know that you’re a very normal human with no magical abilities, and if you’ve swung your sword at all you’ve seen that you have no real skill with it. You just know that you’ve got to kill these unseen colossi to hold up your end of the deal with the voice in the sky. And then a building shaped like a gorilla walks past you https://www.youtube.com/watch?v=3Ckn0mdFyEU
Tap for spoiler
Also the dawning realization that you’re doing something horrible by killing the colossi