Excellent. It's not just the puzzles, the ambience is so good, the story has the exact balance of mysterious, conforting, and ominous, perfectly setting the mood for the unveiling of old secrets. The whole game feels like tasting warm tea with unknown herbs in it.
The sound effects are the best I've heard since The Witness, and every little thing has its own special sound when you click or hover on it. So much attention to detail, I can't believe this is free.
The music is the best I've heard in any puzzle game, period. It goes hand-in-hand with the story's vibes, too. When puzzles get hard, music feels grating to me so I end up turning it off, but not this one. I dare say that it is even better for puzzle-solving than pure silence or nature sounds. I wish Baba is You had this very music on its harder puzzles.
And the content... This dev's games often feature hidden content, but this one takes the cake. "20+ tiny train tracks", it says. LOL. LMAO even.
Also, the game's save folder (in AppData\Local) is called "PlantsPlantsPlants", which somehow doesn't even surprise me at this point.