I have enjoyed every moment with this game. I haven't quite finished it yet, but I'm confident in recommending it. To be clear, if you're looking for a fast-paced game with all the latest bells and whistles, this is not the one for you. The graphics and music are quite simple, and gameplay is as slow-paced as you'd like it to be. However, I disagree with those who call this a "walking simulator." It is very much a game. There are puzzles to solve as well as a story to uncover.
The puzzles are very well-designed. There is no dialogue and no text, yet somehow it's always clear what you're expected to do. Some of the puzzles are quite simple, while others are much more complex, but I haven't found a single one I couldn't solve with a little patience and logical thought. It's not too easy, but it's not too difficult, either. There was only one puzzle I needed hints for - and those hints are provided in the game menu. There are three hints for each puzzle, starting out vague and growing more specific, so you can get exactly the amount of help you need if you ever get stuck.
The story is revealed entirely through gameplay. When I first started playing, I didn't expect there to be much of a story. I was satisfied with the beautiful abandoned abstract architecture and puzzles. The first time I uncovered an unexpected plot twist, my heart skipped a beat, and every one I've found after that has led to even more amazed moments. I'm very picky about storytelling, and this is one game that does it perfectly without ever resorting to dialogue or verbal exposition.
Overall, it's a well-crafted game. Everything in it functions well and it all comes together to form a beautiful whole. It's not for everyone, but I think most people will find it enjoyable and well worth buying.