... With Science!
A scientific study measuring heart rate, sweat levels and body temperature of a selection of players has apparently confirmed Dead Space 2 as the Xbox 360's 'scariest' game. Alan Wake, Resident Evil 5, Dead Space 2 and Condemned were all featured during the test (conducted by Vertical Slice), with Visceral Games' sci-fi horror edging out the competition due to its incredibly stressful opening 15 minutes and consistent level of tension.
None of the players' interest was stimulated during the cutscene that played at the start, at least not until Isaac witnesses his dead wife become a necromorph in a horrific fashion. At least four of the participants found this moment distressing, and were frightened further still when throttled by the orderly, only to have him gruesomely slaughtered by a grotesque creature.
Note that Left 4 Dead 2, Condemned 2, Fear 1 & 2, Dead Space 1, Silent Hill: Homecoming were not considered to be frightening enough for the trial. You can read the comprehensive results over at Gamasutra... and let us know whether or not you agree! We don't, for the record.