I am now playing Moon Castle and I am enjoying it.
It has lots of elements of Myst and Riven but also of Rhem.
It has very good puzzles and you have to look for clues on different places.
Sometimes you have to walk a lot and other times you make a ride.
you can find some hints when you are stuck.
I am planning to make a walkthrough for the game.
The game is already updated and lots of bugs are solved, also the controls are improved.
You can now adjust the speed of movement that makes playing more enjoyable.
I can recommend that game.