Suffers a bit
Some parts are unintuitive, I'm not talking about where to find secrets, but for actual progress (like where to bind the rope and to go right at it's bottom), also the symbols on the model are the "wrong way around" compared to one of the hints, not sure if that was intended.
Hints for the secrets without spoilering:
1.) An empty round hole, nothing to see there?
2.) A city model, any more "uninteresting" round holes?
3.) You've found the key! Did you find everything?
4.) Save paper, print both sides of each sheet!