What at first seems like another thrilling home invasion slasher (think The Strangers or Funny Games) gets twisted into a delicious and delirious surprise that ends up paying homage to Last House on the Left and even George Romero’s Night of the Living Dead. A family celebration devolves first due to the constant bickering among the siblings and then following the startling appearance of animal-masked crazies who pick the dysfunctional bunch off one at a time; that is, until a houseguest begins to fight fire with fire.

As the odds shift, there’s the exhilarating sense that director Adam Wingard (whose slashing handiwork can be seen in V/H/S and The ABCs of Death) certainly isn’t playing favorites, which means any and every character could be the next one to bite the dust. Reminiscent of the buzzy thrills during the first screening of Eli Roth’s Cabin Fever. (R) Grade: A-