The love-struck zombies of “Warm Bodies” swarmed the box office on Super Bowl weekend with a $20 million opening.

The Lionsgate PG-13 film easily led the box office, according to studio estimates Sunday. The weekend of the Super Bowl always means a significant slide in movie-going on Sunday, but “Warm Bodies” still lured many teenage fans.

The film is about a zombie whose love for a human redeems him. Lionsgate, which also released the “Twilight” saga, is calling it a “rom-zom-com” for its mix of humor, romance and the supernatural.

Action films continued to fare poorly in 2013, as Sylvester Stallone’s “Bullet to the Head” opened with just $4.5 million.