First is optimisation, it's not too well optimised to the point where even on a beastly PC it feels a bit sluggish and not so smooth. Graphically pretty, but some weird texture pop-ins, disappearing water and strange physics on occasion. Other big criticism is the music. The music itself is not bad, it suits the mood. The problem is, it loops CONSTANTLY, which is kinda annoying when you've been on a puzzle for an hour and the same 30sec-1min track is in its 60th loop. The flagship puzzle game for music would be Myst III Exile which has a music frequency slider -- music kicks in at pivotal moments as opposed to playing the entire time, and Myst III also used a "self-composing" system, where music would be different every time you played the game. Apart from that puzzles are neat and it's good value for money, and very challenging.
This isn't so much a full blown review, rather a notice to people planning to buy it - If you buy this game outside of GoG it often fails to run on Vista/Win7 without some major tweaking. Fortunately the version sold on this website works well. The ONLY downside is, it occasionally crashes (does this on two of the PCs in my house) so my advice is to save your game often.
