This is a followup to @SorosFootSoldier@hexbear.net 's recent thread for completeness' sake.
I'll state an old classic that is seen as a genre defining game because it is: Myst. Yes, it redefined the genre... in ways I fucking hated and that the adventure game genre took decades to fully recover from. It was a pompous mess in its presentation and was the worst kind of "doing action does vague thing or nothing at all, where is your hint book" puzzle gameplay wrapped in graphical hype which ages pretty poorly as far as appeal qualities go.
So many adventure games tried to be Myst afterward that the sheer budgetary costs and redundancy of the also-rans crashed the adventure game genre for years.
I thought it was notably disliked by most fans of the previous games.
It was super popular and many flaws overlooked for as long as the theorycrafting went on but eventually people figured out it's just a nonsensical mess and the opinion reversed
I think it was only popular because of the porn
As I recall there were several huge breakthroughs in animation pipelining in SFM or something directly related to Elizabeth SFM porn