Near the end when Sam is fighting with that guy underwater, her hair is pulled back by a rubber band or elastic at the start of the fight and at the end when she is swimming back to the boat. But in the middle of the fight, when he grabs her chest, her hair is loose.
When Jared, Sam, Amanda, and Bryce are in the pool discussing whether or not to dig for the ship or report the plane, Jared says "One more thing, you don't repeat this to anyone"....and his lips mouth the word Capiche, but it is dubbed over as "OK", and it's done by someone with an accent.
The sounds produced by the Honda 4-stroke outboards on the triple engine offshore boat are not accurate. They are clearly produced by a low-restriction exhaust on an inboard or inboard/outboard engine configuration. The real engines should sound far more quiet and timid.
When Jared discovers he is running out of air he looks around his buddy (Amanda) and finds her gone. On the Emergency Acsend he still has enough air to keep exhaling (Small bubbles). Yet you see him swimming rapidly to the surface without exhaling. This can cause a lung rupture and every experienced diver will know to keep blowing bubbles in an emergency ascend.
When Jared and Bryce start wrestling in the water and Jared loses his watch, they both have masks and snorkels on. When they surface when the sharks come, neither has a mask on, and Jared gets a mask from Sam to go back down to get the watch.
When Sam gets into Jared's boat after he has put his foot through the floor, she takes her sandals off prior to getting in, but in the next shot showing her climbing into the boat, she has her sandals on.
While being chased after having the accident, Jared jumps out of the driver's side of the truck and runs to the passenger side. There's a Land Rover in the background which disappears in the next shot.
Towards the end of the movie Jared, Sam, and Bryce take off after Primo pulls up next to them, you can see the reflection of a camera in the windshield of the truck as they are going down the narrow ally.
During the first dive to look for treasure, the divers use individual underwater propulsion devices spinning in reverse to blow water on the sand to clear the sea floor. Only problem is, none of them move backward when they do so. Blowing that much water at the sea floor would propel them backwards unless they were tethered, which they are not.
When the crew lifts the cannon and the police pulls up you can see the airbags stopped under the surface of the water. They are very small. As the air released at the bottom it expands, the bags/balloons would be twice/thrice the size at least to have the lifting power (boyancy) to lift a cannon.
The first items of the Zephyr discovered are small (knife, etc). As sand and sediment gradually layered over the ship over time, those small items would have remained in place or settled lower rather than rising above the decaying hull. The highest indication of the wreck would more likely have been the tips of the wooden frame.
Near the end of the movie, Jared opens a loosely closed treasure chest which contains several small treasures. This chest would have been blasted open and emptied, at the very least, when the group used the thrust deflectors to expose the wreck.
When Bryce takes the spear-gun bolt for Jared, you can see the line behind him pulling the spear into his side, and you can see the flesh-colored undergarment he's wearing that the spear goes into, it looks like a bandage around his abdomen.