In my recent attempt at clearing backlog from bundlefodder and rush wishlisted titles discount purchases, I finally installed and finished it. According to steam it took me about 16h (including some alt-tabing to consult a guide or get a beer).
The first 8h were really great, then the game started to get boring, both in the story department, and in the puzzle design.
I stopped caring about gathering stars around the end of World B, and my enjoyment immediately rose to the levels that allowed me to pick the game up again and finish it. The game picks up in quality again in the later levels of C World, and the most thought out and fun puzzles were saved for the Tower level.
Trying to get all the stars indeed feels grindy, and I had to consult a guide a couple of times to get all stars form a given level. In later levels to get the stars you have to set up things in certain puzzles in a way, that will help you open star containing areas in other puzzles.
Without consulting a guide beforehand, on which puzzles to take on first, you will do a lot of backtracking, which sucked my enjoyment of the game for some time.
The story is rather simple, overall predictable, sometimes dialogues are too forced (especially the dialectical method that one AI character tries to use) and philosophical parts come off as pretentious. As has been already stated here, or in the reviews - if you read anything philosophy related, or read 1 or 2 good s-f books about alternate realities and AI, the ideas in the game won't be fresh or appealing.
But there are some genuinely funny tidbits, and the writing itself is pretty good and presented in a concise manner. I think I've read most of the texts, and I found that feeding the information about what caused the human demise to the player, piece by piece, is actually done in a non boring manner. Given all that, one can finish the game without reading anything, if he wants to just enjoy the puzzles.
As I said, puzzles got repetitive for me somewhere around the later half of the second world, but picked up again in the second half of the third world.
The player has to keep in mind, that the puzzles itself are logic-, not physics-based. That means, that there are some predefined states for the objects, e.g. - one fan will lift a box 1m high, but another will lift it 10m high, and you can't change that by, for example, standing on it (but sometimes it's required to stack more objects to change the hover hight). The game guides you on early mechanics, and it shows you restrictions of what you can do (e.g. you cannot put object one on another while jumping high, you have to climb somewhere (on the level lower then your jump hight) to do that), only to ask you to do something you thought you couldn't do, later in the game (like the aforementioned grabbing an object below you).
Overall a decent puzzler with some nice visuals and soundtrack, worth purchase with a discount. I think I will pick up the DLC expansion some time later, as I'm too burnt to do puzzles with the same mechanics again.
