Final Fantasy VII, no questions there. It had 3 disks come on! It's getting a remake for a reason.

Ace Combat 2

Yes, there are many others but this!

EZPZ

Edit: It occurs to me that you mean PS1 specifically! In which case

I cant forget this!

I actually cannot decide between these four.

The QUALITY choice is Resident Evil 2, but I think the one I played the MOST as far as hours is Twisted Metal 3. Couldn't get enough of that game and battling the neighbor kids.

mine has got to be Rayman 3 Hoodlum Havoc on PS2! Literally such a strong good game and it’s such a shame they haven’t brought the old Rayman games on to the Ps Plus to play on newer consoles

For me Resident Evil 1. It was THE game that made me get the PS1 just to be able to play it.

(and funnily enough, the RE1 Remaster was the game that made me get the Gamecube.)

It's a tossup between Raw danger and sly Cooper for me. Raw danger was my first introduction to survival games and the first game that I ever beat. Staying alive in the midst of natural disaster and eccentric storylines was riveting to me. The game had just been a random one that I had grabbed off the shelf back when GameStop had used PS2 games from around $1 to $5 and it ended up being one of my most replayed games. It wasn't until recently that I learned that there were more from the company and I'm hoping I can figure out a way to play them.

Sly cooper, on the other hand, was one of the first games that got me really into the story and the headspace of imaging I was actually the character I was playing. Before when I played games, I never really played them as if I were the character and never really built connections with characters. Sly cooper brought out an imaginative headspace I didn't know I had as a kid. Now I can't play any game without forming a deep connection with the characters and building elaborate storylines in my head while I play.