The first Penumbra (Overture) was an interesting dish of horror and mystery, with a small order of combat salad that was pushed to the side yet occasionally picked at for its croutons. Black Plague, the second game in the trilogy did away with the combat entirely in order to strengthen its horror elements, with puzzles complimenting the tense surreal imagery instead of contradicting it.
For Requiem, the third and final game in the Penumbra trilogy, Friction Games decided to remove one more gameplay aspect in some experimental attempt to strengthen the remaining elements.
It's just too bad they decided to remove the horror aspect in order to focus squarely on the puzzles. Survival Horror? Try Survival Puzzler.