Lots of video games claim to be scary. Amnesia, Dead Space, you name it, if it's dark and things jump out of closets at you, it's "scary". Don't let video game developers tell you what's scary. Let science.
"Usability Studio" Vertical Slice has conducted research into scary games, using a 500-person psychological database, six live test subjects and fancy gear that measured stuff like skin temperature, sweat levels and heart rate.
That's the good stuff. The bad stuff? They only tested on the Xbox 360, and then only tested from a shortlist of games deemed scary enough to be on the shortlist. Some titles considered, but ditched, included Left 4 Dead 2, Gears of War 2, Condemned 2, FEAR 1 & 2, Dead Space 1, Silent Hill: Homecoming, Alone in the Dark and Mass Effect 2. Likely because half of them aren't scary in the slightest.
The four titles picked in the end to test on the live subjects were Alan Wake, Resident Evil 5, Dead Space 2 and Condemned.
In the end, the study found that casual and hardcore players were affected differently by horror in games, core players being less susceptible to scares (because we know basic game design, like what an area looks like when there's fighting to be done).
It also found that across both groups Dead Space 2 was the scariest game of the lot, proving that monster closet gags may be clichéd, but they also work.
So sorry, Amnesia. And sorry, Sherlock Holmes. Maybe next time they'll expand the platforms a little and include you too!
Scary Game Findings: A Study Of Horror Games And Their Players [Gamasutra — Thanks Gavin!]