It's not an original idea - George A Romero's "The Crazies" tweaked the formula back in 1973 - but in the hands of "Trainspotting" director Boyle, it's the basis for a stylish and occasionally very scary movie.
Horror films ranging from The Crazies (1973) to The Shining (1980) to The Blair Witch Project (1999) receive nods, alongside odder visual pulls like Brazil (1985).
Employing a dramatic, even jarring shift in tone from one narrative feature to the next is practically a horror filmmaking tradition, indulged by luminaries such as George Romero (Season of the Witch to The Crazies), John Carpenter (Christine to Starman), and Tobe Hooper (Lifeforce to The Texas Chainsaw Massacre 2).