There are no scary games so far that are truly scary, ie psychological horror. Big slimy ugly bloody monsters are not scary, they're just gross, and apparently that's what most developers think is "scary". They could simply import that The Grudge flash game from their official website, that was pretty scary. I wonder why they don't have plans to import the original Resident Evils over. They would run fine on the iPhone/iPad, especially since RE4 has already been imported.
Silent Hill If they ported ANY of the silent hill games, I would cry with joy... Please Konami? Please Please Please Please PLEEEAAAASSSEEE? (The current silent hill app sucks... ) In case you're trying to find a GREAT horror/thriller, try Se7en. You will s*** your pants...Guaranteed!
As much as I'd kill to have a real Silent Hill game on the iPhone, I highly doubt it, seeing as they already made Silent Hill The Escape, which was pretty medicore, although the posessed wheelchairs were admittedly pretty creepy. As for now, your best be is Prisoner 84 , which shares the same atmospheric horror as the Silent Hill games. And is se7en a movie or a game? I would also like to recommend the flash game Exmortis to anyone looking for a good scare. It perfectly combines a creepy atmosphere with the surprise scares like in the scary maze games. It makes you think that you'll be scared by one thing, then something else surprises you. For a flash game, it's surprisingly scary.
se7en is a movie with Brad Pitt and Morgan Freeman. This thread is shifting towards scary movies so... Silence of the Lambs was great. It wasn't especially scary, but it was a great movie.