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.
Starfox 64. I played it at Toys R Us......oh, uh, kids Toys R Us was a toy store that had been around for like 80 years. And everybody knew it was never going to close, because there was always going to be more kids.......and then it closed.
Anyways, they had a demo unit you could play. It reset every 10 minutes. Then Mario would pop up and say "THANK YOU FOR PLAYING NINTENDO 64, WHO'S NEXT???"
And like a stupid teenager, I yelled "I AM!!!" as if it were voice activated. It wasn't. I was just a dumb teenager telling at a CRT tv.
One time I got so invested in it, that I didn't even notice a kid was behind me for like 20 minutes. And eventually he said "Excuse me.....you went 3 times in a row. Can I try please?"
Man I felt like an ass. He probably felt like I was bullying him out of playing. I was twice his age, twice his size, and even compared to other kids my own age I was always a kid who was at the top of the food chain. I genuinely didn't see him, and thought I was alone. I let him play all the turns until his family made him leave.
But those visuals.....THE RUMBLE PACK???!!! OH MY GOD!!! THE CONTROLLER SHAKES WHEN YOUR SHIP GETS DAMAGED!!! And it had 3D space ship flying and voice acting, and oh my god.....
It was all very overwelming. I'm not saying Mario 64 is a bad game. I loved it. But Starfox 64 was the game that made me buy a game for a console I didn't even own. I was THAT sure that I'd have to have an N64 one day.......that day was like 6 months later.