Visible crew/equipment: After Leslie Tiller is stabbed with the garden shears, when Nicholas chases after the hooded figure, just as he dives over a table with potted plants the blue crash mat is visible under the table. (Slow motion is not necessary.) (01:07:00)
Factual error: At the end of the film, SGT Angel gets into his Police car Subaru Impreza, and on the bonnet it has the writing 'Sandford Constabulary'. This is incorrect, it would in fact be 'Gloucestershire Constabulary' as established at the start of the film that Sandford is in Gloucestershire. A Constabulary is always named after the County, never after a tiny village within that County. (01:49:35)
Trivia: There are brief cameos at the start of the film by Peter Jackson as Bad Santa, who stabs Nicholas, and Garth Jennings as the Crackhead who holds hostages. Later, Cate Blanchett appears as Janine, who is hidden behind a surgical mask, and from whom Nicholas is estranged. And the film's director, Edgar Wright, is seen as the store employee pushing the cart when Nicholas walks towards the manager's office.
Revealing mistake: When the Sergeant has the shotguns in the backpack on his back, and you see a close up of his face, you can see that the shotguns do not have triggers. On plastic prop rifles, the trigger is usually molded into the trigger guard in the pulled back position, and you can see this on these prop shotguns.
Continuity mistake: When Michael attacks Nicholas in his hotel room, during this scene objects being broken or shoved (such as stuffed monkey, radio, lamp, picture) change their position, or the characteristics of the actual damage, change from shot to shot. Additionally, when Nicholas is slammed into the picture it begins to fall forward, but next shot it rests upright against the wall. (01:17:30)
Continuity mistake: Immediately after Tim Messenger is killed, Angel runs to the top of the church spire. As he exits the door onto the roof, the remains of the small spire that fell on Messenger can be seen on the right hand side of the screen. In the long shot of the roof that immediately follows this, the remains of the small spire are missing. (00:57:10 - 00:59:30)
Continuity mistake: When Nicholas is asked for his autograph, for breakfast, his signature, as well as the ones above and below his, differs between the side and top shots. (00:25:00)
Revealing mistake: When Angel and Danny jump into the skip, you can see the boxes under the rubbish have been placed there specifically. (01:41:00)
Revealing mistake: After Angel gets shot in the vest, you get a good closeup of his bandoleer of shotgun shells. You can see the gold paint rubbed off on the primer side of the cartridges, revealing the red plastic underneath. You can also see that the end of the round either just has paper stuffed into it or is completely empty. A real shotgun round will have a brass cap/primer and the end will either be folded completely over (like the shutter of a camera) or show a rifled slug inside. (01:37:20)
Revealing mistake: When the officer holding the double barrel shotgun has it broken open to reload it, you can see that the primers have been dimpled, meaning that they've been fired. The rifle is closed up again without the spent shells being replaced. (01:41:10)
Deliberate mistake: The floating contact mine that explodes at the end of the movie would never have been put in an evidence room in a police station. Barring that error for the plot's sake, FCMs weigh 450lbs and would have required a hydraulic crane and a cart to move it, not just a couple of guys. They also did not contain clocks. (00:42:40)
Revealing mistake: When Tim Messenger gets the spike dropped on his head you can tell he has been swapped with a CGI look-alike. (00:56:00)
Answer: Just before "Auntie Jackie's sisters' brothers' boy' legs it, Danny is looking at the DVDs in the supermarket and there's a copy of Shaun of the Dead in the bargain bin...albeit the Spanish version! Only £4.99! It was released as "Zombie Party" in Spain but has the same front cover as UK release.