Kill (2011)

Six strangers wake up in a strange, empty house frilled with tropical decor. After realizing that they are locked inside, with cameras watching every step they make, they find out that each one of them is a winner of a contest involving a dream vacation on a mysterious tropical island. To their absolute horror, the strangers are told through a built-in P.A. system that the only way they will ever see their loved ones again is if they fight each other to the death. Last person standing, wins. After a brief period of shock and disbelief follows the slow but gradual breakdown of this mini-society as every character is reduced to using their animal instincts. And thus, the fun begins.