Collet-Serra ensures that we feel the risk of every stroke between his heroine and her safety. The action is visceral and immediate, but crucially contextualized by a helpful array of wide shots and bird’s-eye views.

After a summer glutted with films pushing punishing, redundant set pieces on grand scales, we finally have a film that is patient, atmospheric, and that delights in delivering escalating thrills of a smaller but more valuable variety.

What could have been mere summertime chum is actually one of the more cleverly constructed B-movies in quite some time.

What makes the film churn so forcefully for so long is Jaume Collet-Serra's visual acrobatics.

Surrounded by so many bloated, unsatisfying movies, The Shallows is as refreshing as a quick dip on a hot summer day — preferably in a pool, not the ocean. They tend to be safer and less shark-infested.