Wow, difficult choice. Shoutout to Monkey Island 2 and Eye of the Beholder, but I guess they were good continuations (even though EoB was a new series, but continuing that RPG power) not breaking new ground. But Sonic the Hedgehog, A Link to the past and Civilization are all games that were influental. My choice is Civilization, because it really cemented the name Sid Meier and is the blueprint for a lot of games even today. And I never forget this intro:
https://www.youtube.com/watch?v=PtK388b9drE