This game is beautiful in terms of narrative and visuals. Don't be afraid to keep the settings up, because it's very well optimized and shadows have a functional use as another point of reference to help you know where physics objects are in the scene.
The puzzles themselves are challenging and keep you thinking in new ways, but they aren't too difficult. Only 2 (out of more than 30) actually gave me enough trouble that I had to look up the answer. One I felt stupid for not being able to figure it out, the other was genuinely confusing. You'll probably know which one I'm talking about when I say the words "Observer-expectancy bias".
For 20 bucks, it's on the short side with 1 to 2 hours playtime, especially since I would've preferred there were more of the interesting abstract puzzles near the end, but I'd still say it's worth full price and definitely worth playing in general.