i looking for horror games for inspiration...

[Googolplex]

When you only played the Demo of Penumbra, you should take a glance of the full game.
I would hope, that there are some other games like this kind of horror/puzzle games. But as I know, there are no others. Penumbra & Amnesia are the only ones, that are good horror games (for me).
I'm searching for some others, but I could never find them.

So, I can not list an other horror game, but I have a small one with some puzzles and not only with shooting monsters.
Shade: Wrath Of Angels

And if you search a great game with full of puzzles, then try this one:
Indiana Jones and the infernal machine

I played this and as a fan of Penumbra, I loved the puzzles in Indiana Jones. The game is full of hard puzzles!
A very good adventure!