There are horror films which bend the boundaries of the genre, which deal with the psychological, the suggested or the subtly thematic – and then there are the sheer, in-your-face, terrifying horrors which threaten to drain your body of sweat and lock your jaw shut forever. This is one of the latter. There have been sequels and remakes and plenty of pretenders looking to steal the film’s terrifying demonisation of those strange folk who live in the woods with a link to the local abattoir, but this is where it began. Its methods are basic: innocent kids (a guy in a wheelchair! A blonde girl!), a creepy house in the forest, nighttime chases through the trees, the sound of the chainsaw, the killer’s mask… This is high-energy peril, right up until the frenzied final scene on the road as dawn arrives. Simple and sick.