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.
Actually halo is antifascist
In the first game you have the genocidal theocrats trying to wipe out humanity, and you have humanity represented as the roman empire in space. So both sides are basically fascist. And the player character proceeds to accidentally almost wipe out all life in the galaxy by trying to find the biggest gun and use it against the baddies. Cortana has to step in, call you a nincompoop in a bizarrely british accent, and inform you that Halo will wipe out all life in the galaxy. The lesson here is that you should stop and think instead of uncritically participating in the cycle of fascist violence.
In Halo 2, you play as a military leader participating in a theocratic genocide, whose cultural traditions have been turned against your species to turn you into a willing slave of the rule caste who does their dirty work and has no honour so you'll stop asking pesky questions like "Why are we killing the humans". You meet heretics, a light bulb, and a big venus fly trap who slowly deradicalise you, until one day your people are genocided and you team up with the people you oppressed. The lesson here is that you should stop and think instead of uncritically participating in the cycle of fascist violence.
In Halo 3, Earth is invaded and the covenant find a portal to the Ark, through which Cortana says there is a way to beat the Flood. Lord Hood wants to stay at Earth and go down in a blaze of glory, but Master Chief and arbiter who have learned their lessons from the last two games, say they should go through the portal and see what Cortana's big discovery is. The lesson here is that you should stop and think instead of uncritically participating in the cycle of fascist violence.
In Halo ODST it turns out that Huragok are slaves actually and there might be something to be gained by saving them from the covenant instead of killing them like you have been the whole game. The lesson here is that you should stop and think instead of uncritically participating in the cycle of fascist violence.
In Halo Reach, Noble Team try to go down in a blaze of glory defending Reach, but Halsey gives them an AI she says has the secret to winning the war, and it turns out Cortana has the coordinates of Halo. The lesson here is that you should stop and think instead of uncritically participating in the cycle of fascist violence.
In Halo 4, Captain Del Rio doesn't want to risk damaging the Infinity because it's a ginormous phallic substitute for his fragile masculinity. Chief and Cortana have actually been spending their time exploring and studying the lore, and they go rogue and save the world. The lesson here is that you should stop and think instead of uncrtically participating in the cycle of phallic symbols
What can I say, the bungie era had better writing