Some would say this is a guilty pleasure movie at best, I say it is just a pleasure. Let Sharknado make you feel guilty, Deep Blue Sea is a well-constructed survival horror.
On a floating research station in the middle of the ocean, Stellan Skarsgaard, Thomas Jane, Samuel L Jackson, Saffron Burrows, Michael Rapaport, Aida Turturro and LL Cool J are studying ways to increase intelligence in sharks (something something helping Alzheimers). When the sharks get too smart, they turn on their caretakers and start picking our celebs off one by one.
This movie is kind of famous for the scene where Samuel L Jackson gives one of his inspiring speeches and then gets surprise-eaten by a shark (spoiler for those new to the internet). The truth is, none of the characters are safe at any moment. You have not only the sharks to worry about but the rapidly sinking base makes for some Poseidon Adventure moments as well. Renny Harlin can stage some action is what I'm saying. The Long Kiss Goodnight and Die Hard 2 weren't flukes.
Lots of good tension and perfectly acceptable performances from the all-star cast. Nothing to be taken all to seriously but lots of fun.