This review contains spoilers

I am not sure how to feel about this game, not sure at all. Some parts are great, other parts are absolutely atrocious. Some parts were such a joy, some parts are downright painful. One part made me want to keep playing it forever, another part literally gave me a mental breakdown (or something close to it).
I am glad I have finished this game. Not only because I have completed a great challenge, but also because I don't have to suffer through this game anymore.
This game can feel so rewarding, yet also one of the most painful experiences I have had in recent years in gaming. (Do note I said it [i]feels[/i] rewarding, you gotta have an intrinsic joy for puzzles to keep that feeling though.)
Do [b]not[/b] play this game if you do not [i]really[/i] enjoy puzzles. This game is almost only puzzles. There is a bit of philosophy (which you will be too mentally engaged/fatigued to think about), but there is no story or music or lore or reward or anything. The only reward is more puzzles. You complete puzzles so you get to complete more puzzles so you can complete more puzzles. It is like a big Sudoku book, and once you complete one you get to complete 5 more. Each book twists the formula a bit, but by the end of the last Sudoku book you won't want to play Sudoku anymore. (Maybe this game is best experienced, where you complete one puzzle a day or only play when you have nothing else going on or only complete one section a week/month/year or something. I don't know...)
If you are someone who finds puzzles to be something that pads out a game, someone who sighs gently when they get stuck at a puzzle in a story game, or only played Portal 2 for the witty dialogue and story first and the puzzles second... then do not play this game.
If you do enjoy puzzles, then go ahead and play the game. At times you should have fun, but to limit suffering allow yourself to look up hints and guides and just understand you will never 100% this game on your own.
This is not the sort of game you complete without a guide or some hints, even without going for secrets you will certainly need help.
The Challenge looks actually interesting at first, but probably only because I like the music. Also I [b]love[/b] the environmental puzzles. I just think it is a bit naff that there seems to be no reward for finding them all.
Overall... get it on sale if you are willing to play with hints or not complete the game.
As for those wondering, I completed 90-95%+ puzzles without any sort of guides or hints. However, I really threw in the towel at the end. I also threw around a lot of swear words.
Also I activated all the lasers, which I don't think you needed to do to get the "Endgame" ending... so yeah.

Reviewed on Feb 25, 2023