As the zombies break through Shaun is wearing a red bandana while wielding the rifle this is reference to Christopher Walkens character in The Deer Hunter. When Shaun is shooting the zombies in the windows, the camera switches to one from Simon Peggs point of view, with only the rifle sticking out of the shot. This is a homage to gaming, more specifically first person shooters such as Doom and Timesplitters, which was earlier played by Ed during the first scenes.