Could have been better, way better. This is how it should have ended. I came in expecting this to be absolute trash, like it should have premiered on SyFy, but it wasn't that bad. There's really only two things I'd like to point out and it all occurs in the last 10 minutes. This review contains spoilers....
Okay, so we finally hit the point of the movie where they need to get to surface before one of them (who was bitten by a shark) bleeds out. Not only are they swimming in the dark with little to-no vision of these massive sharks around them, but they have to sit for 5 minutes to stop the Nitrogen Bubbles from going in their brains -- which would kill them too! This was the moment where I thought the movie would SHINE, 5 minutes -- in the dark -- in ultimate terror -- with sharks all around them? Let's do this!!!!
Nope.... the 5 minute timer 'starts' and no more than 15 seconds in, the man from the boat calls out 4 1/2 minutes to 3 minutes left. We are just starting this "5 minute" scene and it lasted no more than 45 seconds, if that. I'm not saying it should've lasted the FULL time, but the audience missed out on all the suspense it was building.
Then, we get to the surface to have this corny scene of the sharks attacking them, even to the point where they were being pulled onto the boat and one came up out of the water to bring one of them back under again... Now after all of that I'm rolling my eyes like "corny? yeap --- that all just happened," but then I was pulled back again.
Everything we just saw from her finding her sister, escaping the cage, the climb, getting back on the boat --- was all an illusion from Nitrogen narcosis. I was like YES! This movie just mind f#$%ed me and we are getting the dark reality of this tragedy. It's the darker side of the stereotypical "happy" ending. I was with it!
BUT!!!! once again, DENIED! The following, and closing scene, shows her snapping out of the hallucination to have the coast guard comes down, rescue her and bring her back to the surface.... yawn.
Movie ends right as she's hitting the surface. No follow up. No extra info. No dramatic scene with the sister. Nothing.
If I could change anything: End it with her in an hallucinated state and the oxygen tank meter reading zero. I know that's dark --- but man, that would have been an ending.