SMB
DOOM
SF2
Mario 64
GTA 3
Those are the 5 god tier games in where they were not only great, but introduced new gameplay experiences. As much as I like the original MGS on the PSX, it's not god tier. Just very good. Goldeneye does not qualify as GOD tier either....Half-Life was a much better game. An argument can be made for the Original Halo over Goldeneye IMO.
An argument can be made for Madden to be included in this list as well, but it's a franchise that has really iterated on a formula over time. Not sure which one will qualify as the biggest jump. It is probably Madden 95.