Have you ever dived with some folks who just don’t have it together?

You see them nervously set up their gear, karate chop their way through the water and come dangerously close to round-house kicking centuries-old coral. You can’t help but feel anxious—bad divers simply lessen the experience for everyone else.

Now, imagine the horror of seeing this unfold for 90 minutes on the big screen.

Any passionate diver can attest—47 Meters Down: Uncaged is a true horror-fest, but not for the reasons the writers imagined.

This film, which was released in theaters August 16, is a follow-up to the surprise success 47 Meters Down. The first installment definitely had its issues but I can see why viewers enjoyed it as a popcorn horror flick. The sequel fails in almost every aspect, continuing to prey on fears of sharks and scuba diving without ratcheting up the ridiculousness to take the audience on a fun thrill ride (read up on the rise of the bad shark movie—who can forget Sharknado?).

47 Meters Down: Uncaged will make serious divers laugh (or cry depending on how seriously they take buoyancy control), non-divers nervous to ever pick up the sport and everyone just a little bit annoyed that they wasted an hour and a half.

WARNING: This article contains spoilers for the film 47 Meters Down: Uncaged

Here are some of the most ridiculous mistakes in 47 Meters Down: Uncaged.

Kicking and Screaming

This will follow me to the grave. I will never, for the life of me, understand this creative decision. For some crazy reason we follow four teenage girls as they take on cave diving for the first time. That’s right, one of the most specialized and dangerous forms of diving. And they do it all WITHOUT FINS.

We follow our heroines to a secret escape on the Yucatan Peninsula where they sneak off to a secret cenote (although they refer to it as a lake in the movie). Luckily, local divers and archeologists have implanted a floating dock here and stashed fully functional dive gear for four, just waiting to be used.

Perfect! The girls take the opportunity to kit up and take just one quick spin through the first cave loop. What could go wrong?

But there’s one issue: The full set of scuba gear, including filled tanks and full-face masks with communication systems, does not include fins.

One of the characters expresses her concern: “But there’s no fins.”

“C’mon,” is the reply. “It’s the first cave. We’re not diving the whole city.”

Just to make one thing clear: Diving without fins is like driving a car with four flat tires. You are going absolutely nowhere fast.

Not only are these rusty divers (“It’s like riding a bike,” says one.) going into a cave system for the first time, but they’re somehow planning to do it barefooted.

The difficulties become apparent from the get-go. The divers are forced to scoop through the water with their hands to get anywhere. It’s a miracle they don’t run out of air within 10 minutes (these air gauges read in a big, bold percentage rather than PSI or BAR, presumably because the filmmakers figured the audience is too simple-minded to grasp the concept otherwise).

The four divers exit the open cenote pool and begin to reach a more confined overhead environment. Anyone who’s dived in caves or caverns knows that in many cases it is incredibly easy to kick up silt. One misplaced movement will cause the viz to go from 200 feet to zero. Yet, these novice divers are doing just fine karate chopping their way around (until one gets spooked and knocks over an ancient Maya pillar, reducing the viz to nothing. But that’s neither here nor there).

“I can’t believe we’re doing this,” says one protagonist as they gleefully descend.

Me either.

Jaws Takes a Vacation

Oh, did I mention there are blind great white sharks in this cave?

Divers have enough to worry about in an overhead environment, but the ante is seriously upped when you throw a couple of blind sharks that can weigh over a ton in there.

The explanation is as follows: A white shark found an opening from the ocean and meandered into this cave system many years ago. It was somehow able to feed (and presumably reproduce over multiple generations?) in the environment, while also adapting to the dark conditions by losing its eyesight and enhancing its other senses, a la the Mexican tetra (Astyanax mexicanus), which lives in freshwater caves and grows to be a few inches long. The white shark also adapted to fresh or brackish water and is simply waiting for its chance to snack on some unsuspecting divers.

A major plot point also involves a group going out on a glass-bottom boat tour to see great white sharks … off the Yucatan Peninsula. Don’t get me wrong: I’m not here to say where white sharks can and can’t go. These creatures pretty much rule the ocean and are known for navigating far and wide (see Ocearch’s tracking system if you don’t believe me). But they generally prefer temperate coastal waters and are not known for hanging out in tropical areas like the Mexican Caribbean. Even if a white shark or two might head to Cancun for vacation, the frequency is no where near enough to justify a shark-watching tourism industry.

And how exactly have these sharks been surviving in these caves? There are freshwater fish and crustaceans that can live in this environment, but nowhere near enough to sustain one of the ocean’s most voracious fish. A 2013 study found that about 66 pounds of blubber would provide a white shark enough energy for about 12 days. So these caves must have A LOT of whales, seals (or trapped divers) swimming around.

This is where the movie borders between Jaws territory—a film that preys on real fears and has negative consequences—and Sharknado territory—a film that is so blatantly ridiculous that it has no negative effects. The end result is really in the eye of the beholder.

“No tourist could ever find this place.”

The movie persists in basing major events on shaky science: This cave system has a large enough opening for people and white sharks to pass through yet the sharks decided to stay and reproduce in the low-energy cave rather than swim to the thriving ocean ecosystem.

Ancient Mayans were able to build a burial shrine with solid walls and pillars underground in a region that is known for its extremely porous limestone bedrock (sculptures that look suspiciously like the work of famed underwater artist Jason deCaries Taylor make an appearance).

The passage between cave and ocean involves an incredibly strong down current that doesn’t quite match with reality, and the protagonists sustain a few major shark bites and have nothing but a bloody leg to show for it when all is said and done.

The list goes on.

Of course, part of the movie-going experience is suspending disbelief for a couple hours, munching on popcorn and enjoying the ride. And I know that “well, actually” guy is no fun at parties, but I worry that this flick is not in on the joke.

So, call me a party pooper but I’ll stay here wagging my finger at Hollywood until it decides to consult at least one diver for its next underwater epic.