A beautiful woman trapped on a rock by a big shark. That’s the plot of The Shallows. The woman is played by Blake Lively. The shark is played by some pixels. The rock plays itself.

Something about the film recalls a line by comedian Louis CK: ‘Do you think that sharks would be embarrassed if they knew we could all see their fins sticking out the top of the water?’ Shark-attack films are inherently silly, and The Shallows is no different. Interestingly, it seems to be in on the joke only about half the time. The laughs come from the expository dialogue – Lively’s character often clunkingly ‘thinks aloud’ to herself – as much as from its mischievous willingness to traumatise its heroine.

Due to its blonde-heroine-versus-malevolent-nature subject, The Shallows has been compared to The Birds, but it’s more like a remake of Psycho: a remake that’s just 20 minutes of a naked woman showering followed by an hour of her wrestling with the knife-wielding assailant. It’s about as one-note, voyeuristic, and diverting as that description suggests.

If you arranged a quality-spectrum for killer shark films, with Jaws at one end and Sharknado 3: Oh Hell No! at the other, then The Shallows would swim back and forth between both extremes during its brief 86 minute running time. At its best, it’s a serviceable creature-feature that does exactly what it promises.

Director Jaume Collet-Serra has access to better special-effects technology than Steven Spielberg did in 1975, which means that he can have his Great White flip into the air like in a David Attenborough documentary. And while he doesn’t have Spielberg’s genius for characterisation – even his shark has a bolted-on backstory – he can ably manufacture a sense of jeopardy out of a situation that can only end one way. You’ll grip your seat’s armrests even as you scorn the goofiness.

In the end, your enjoyment of The Shallows depends on your susceptibility to dumb B-movies and to Blake Lively. Both are guilty pleasures that you can elect to indulge or ignore.

We forget, in our contemporary reverence for Jaws, that its original reviews were relatively dismissive. The New York Times called it ‘the sort of nonsense that can be a good deal of fun’. The same can be said of The Shallows.