I always thought, that Penumbra is one of the games, that is full of ideas and puzzles. That's still right, but I found a game with more such kind of puzzles.
OK, FG makes horror games, but without in combination with puzzles, they were nothing. The puzzles are this, what player really makes fun and what distinguishes the game with it's ideas.
Take a glance of...
Indiana Jones and the infernal machine
This is an old adventure game, but as I play it, i find out, that the game has more puzzles as my beloved Penumbra.
You can not compare this games each other, but the game has also many ideas and looks like more puzzles as Penumbra.
Great game! And in the pyramids of salomon it is scary too.
Everywhere are hidden transitions and the puzzles are so thoughtful, that you never solve it without looking in the "complete solution" by some people.
I love it and I can recommend this game to everyone who loves Penumbra and Amnesia.
It is an other kind of game, but the puzzle stuff is even better.