We know so frighteningly little about the ocean. Hands down, the best shark-themed film (that I've seen) since 1975. The practical effects are fantastic, the CGI is great too, and Blake Lively gives a very good performance, pretty much carrying the entire film on her own. But what impresses me most, and what The Shallows does more proficiently than most creature features, is make you fear the space, not just the monster. The shark is scary enough, but Collet-Serra does such a wonderful job injecting fear into every inch of the blue that it inhabits. It makes you think: if these are the entities that inhabit the shallows, if these events can transpire along the surface, what sorts of horrors are gliding through the deep?