Galatea is a weird one for me, because I always butt my head against it for reasons that might not even be its fault.
As a story, it's wonderful. Galatea herself is a great character, a little bitter and capricious, entirely defined by her sculptor and fundamentally unable to have a life outside of his memory. It's a fantastic character study.
As a game, I always struggle a lot. You're supposed to pick up on keywords in Galatea's responses to follow conversation threads, but not every word you'd expect to get a response is a keyword, and some keywords are sort of implicit, but it's difficult to get at certain concepts you want to talk to Galatea about. The effect for me is a sort of dialogue maze where I talk round and round in circles until I give up and look at a walkthrough so I can enjoy the writing more.
I think it's interesting that the game knows its own limitations in this respect. In some of the happier endings, the PC seems to have a moment of clarity where they see Galatea as a personality rather than a living statue. This may just be my own interpretation, but I see a parallel here with seeing an NPC as a living conversation rather than a list of topics to run down. I think this is a lovely bit of writing which could merge the player's feelings and the PC's feelings at its best. I wish I didn't keep running into conversation loops so I could experience it. (The effect is compounded if you exhaust a topic early on and your character sneers something like "how can I treat this art as real when it has such a limited encyclopaedia?" I guess this is supposed to anticipate and play with criticisms of the game, but I wish it wouldn't remind me of its own limits when I'm trying to meet it on its own terms.)
This is all unfair, really. Galatea was one of the first works to really explore and improve conversations in IF (in my limited understanding of IF history), and Emily Short has built off this game wonderfully - her later game City of Secrets has the best conversation system I've seen so far. Once I looked up walkthroughs and read the work as a collection of stories rather than a conversation, I liked Galatea a lot more, but I think I've come along too late to appreciate it in its proper context as an influential game.
I'm leaving the game unrated because I don't think I've given it a fair shake. Maybe I just prefer puzzle games?