Oof that's a hard choice between King's Quest, making the point and click adventure popular, and Elite which is still going today and popularized seamless open world gameplay.
1942 was tons of fun, I played River raid more though (also 1984)
Elite had me totally addicted to space exploration, both in University playing Elite Frontier Encounters after classes in the computer room, coming back to uni in the evening to play together with friends, and again in 2015 when Elite Dangerous came out.
https://forums.frontier.co.uk/threads/exploration-quest-for-the-loneliest-planet.132053/
But I'll vote King's quest as that led to Myst which became one of the first games that became main stream. Point and click adventures are still everywhere today on everything.
