Critics are heaping praise on a surprise hit of the North American summer blockbuster season - Crawl, a thriller-horror about vicious alligators.

Crawl, starring Kaya Scodelario (Skins) and Barry Pepper, has received unexpectedly strong reviews, debuting with an 88 per cent score on Rotten Tomatoes.

The film follows competitive swimmer Haley (Scodelario) who attempts to rescue her dad from flooding in the midst of a devastating hurricane - but must fight against a swarm of deadly alligators that have arrived with the rising tide.

Critics have praised the film for its clever, low-budget thrills, and its relentless, genuinely terrifying pace.


Vulture's Angelica Jade Bastién described the film as "near-perfect".

"Crawl is a great example of a simple story exceedingly well-told," she said. "It's a bloody adventure full of teeth-gnawing turns of fortune, mordant wit, vicious gator kills, and surprising tenderness - that clocks in at a blessedly fleet 87 minutes."

The Verge described Crawl as an "antidote" to this year's slog of disappointing reboots.

"It ... maintain(s) its tension in a way that outshines many of this year's summer thrill rides ... It's silly, sure, but it also has a pleasing clarity — nothing in this movie feels like it was frantically and haphazardly rewritten in the editing room."

NZ Herald reviewer Tom Augustine called it a "blistering white-knuckle thriller".

"Crawl is here for a good time, not a long time, but is undoubtedly one of the best, most thrilling, most absorbing experiences I've had in a cinema this year, and well worth making time for."

Polygon wrote: "The alligators, the tight crawl space ... and the hurricane all work separately, but together they create some claustrophobic, truly terrifying moments, taking Crawl from a simple creature feature to a tense disaster film that mashes the outlandish and suspenseful into chompingly good fun".

Crawl is in New Zealand cinemas now.