If you got through the first pages of Recherche du Temps Perdu, you may remember Proust once talked about madeleine bringing back a bunch of memories. You may remember it even if you didn't. It's become one of those literary cliches.
Here it's root beer. Root beer, the poor neglected cousin of Coke and Pepsi, and I've always preferred it, too, and I suspect I have more brethern or sisters than could be polled. (I in fact made a far more flippant reference to it in Threediopolis. It made a tester laugh. I'm still proud of that.) But the root beer is sentient! It's hidden under a porch, and it'll bring back memories. Like the meat in Douglas Adams's Restaurant at the End of the Universe, it's okay with you digesting it. And yes, it's a bit unnerving, too, but it all makes sense. Sadly, this state will only last for twenty to forty minutes.
That's more than enough for a lot of memories for you-the-character, and it brought back memories for me as well. Memories of chugging one two-liter bottle too much while studying, or of a pop can with the Minnesota Golden Gophers logo and 1984 Big Ten schedule on it. Or maybe of leaving root beer so long in the fridge, proud of my restraint, it went flat. Memories of mixing root beer with different types of ice cream to make a root beer float. (Don't get me started on ice cream flavors. Seriously.) Heck, even Red Bull drunk once every two years brings back memories beyond "this is why I don't drink Red Bull."
The character has different memories, of course, combinations of happy and sad. Alcohol is briefly touched on without judgement from the root beer or narrator. As a teetotaler, I felt a bit superior, though.
I didn't once I had The Choice. What is it? Well, you can be selfish. I saved the game and took the selfish one first, then took the selfless one. I immediately rationalized that I could do what I knew from the selfless one once I went selfish, or it would have happened anyway. I'd like to think I would, in real life. But things probably don't quite work that way.
I think the final choice is strong and well-placed enough not to spoil here, and MNiS would have been well-done without it. I place a high value on games that let you think in your own way without being all "I'm making you think" or being too unstructured and general and MNiS hits that spot for me.