They both made me crap my pants, and sweat buckets, but I thought Penumbra had some pretty obtuse puzzles, and some of them made no sense. I did like Penumbra's art style better, but I personally liked Amnesia better. What do you think? :P

I'm excited for A Machine for Pigs, It look really good.

I don't know, the reason these ARE scary is because you are helpless and have no one to turn to. So I think the Co-op would just ruin it.