Shaun of the Dead is tribute to so many well loved Zombie classics, but at it's core the Zombies only play a small role in the main story. Simon Pegg and Edgar Wright use the symbolism of the Zombie invasion as Romero did his first films. It is a smartly written comedy filled with so many pop culture references, many are missed on the first viewing. Here are a few:
Throughout the film, we see references to a fictitious pizza chain called Bub’s Pizza. This is a reference to Bub, the smarter-than-average zombie from Day of the Dead
Ed yells over the phone to Shaun’s mom, "We’re coming to get you, Barbara." This is a take on the line, "They’re coming to get you, Barbara," from Night of the Living Dead.
Shaun tries to make reservations at an exclusive seafood restaurant called Fulci’s. This is a nod to Lucio Fulci, famed Italian horror director.
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Even the death scenes pay homage to the classics.... In this clip, the gang take refuge from the Zombie attack in the Winchester, Shaun's favorite pub. Suddenly David(Dylan Moran) gets pulled through a window and torn apart by a crowd of Zombies, but in a very familiar way. The scene is almost identical to that of Captain Rhodes in Day of the Dead.