Way to make me feel old, I don't know any of those games.
Where's my late 90s early 2000s gamers at?
I'm going to nominate:
Fallout (1997) for plot twists and introducing (to me at least) open world role playing.
Fallout 2 (1998) for further plot twists
Max Payne (2001) for stealing bullet time from the matrix and putting it in a game
Mafia (2002) for being a kick ass game that would blow your mind, by making 6 hours of your night disappear, and not lifting the lid on that plot twist before you heard the birds start singing, and realize that you should probably hit the shower and get to school.
If Fallout introduced you to open world RPG's, that means you missed Daggerfall.
Arguably the greatest open world RPG of all time.
That was the game that absolutely, completely blew my mind with its openness, freedom, and scale (none of which were matched by any following TES game).
Well worth blocking the phone line for an entire night and running up a phone bill that'll get you yelled at by your parents, to download the 140MB installer.