For a film that can be summed up pretty much in five words — snowboarders get stuck on chairlift — Frozen is remarkable for wringing a maximum amount of tension and terror out of its minimalist concept. Credit writer/director Adam Green, who takes but 20 minutes to set up the relationship dynamics — between best buds Lynch (Ashmore) and Dan (Zegers), and the girl, Parker (Bell), encroaching on their lifelong bromance — that will intensify and unravel once the trio find themselves dangling mid-air on a Sunday night in a ski park that isn’t due to reopen until the following Friday.

That none of the characters are immediately likeable — they prefer to bribe their way up the slopes rather than fork out for lift tickets — actually serves Frozen well, as, once trapped, their foolhardy escape strategies are consistent with a certain smug sense of privilege. But what really elevates the film above straight-to-cable filler — and what makes it a worthy complement to recent lo-fi thrillers like Paranormal Activity and Open Water — is how effectively Green creates a sense of claustrophobia amid the wide-open space, where the quandary of how to take a pee while wedged in a chairlift is but the first in a merciless series of hardships that includes snowstorms, hunger, frostbite, wolf packs and the uneasy relationship between skin and cold metal.

However, in a film that, early on, mocks snowboarding for being “too emo,” Green displays his own weakness for syrupy string scores (that undercut the air of wind-whirred desolation) and late-act character-development sob speeches that prove inconsequential to the matter of whether these people will get out alive. Frozen works best not when it’s trying to make you care about the lives of its characters, but rather when it makes you feel like you’re trapped up there with them.