In the scene in which Ricky Nelson is being driven through town on top of "Mustang Sally", the car keeps switching between having a hubcap on the front driver's side tire and not having one. The only time we see the car actually lose a hubcap is a few scenes later when it runs into the bus, and we see a hubcap roll off in the dust.
Just before Richard turns the volume up on the car stereo at the start of the episode, we can see it says "No discs loaded" yet he is listening to music. If he was listening to the radio, it should show the station.
When Richard tumbles down the steps, for a brief second you can see there are a few Stephen King novels scattered on the floor, obviously self-referencing the author within his own series. Two of the visible titles are Pet Sematary and The Tommyknockers.
When he goes to bed at the start of the episode, Mr Umney sets his alarm for 6 o'clock. We then see a shot of the clock turning with the alarm set to 10 o'clock. And although the hands are turning fast, the second hand isn't moving.
Danny's tombstone says 1994-1999, which makes him 5 years old at his time of death. But Clyde read the story on Sam's laptop and later said that he was 6 years old.
Clyde says "As they say in your world, I'm the Man." But how did he know what they said in Sam's world? He didn't have any knowledge of the real world, other than what Sam told him.
Despite being supposedly set in Crouch End, London, and many references to London being made throughout the episode, the settings are very obviously Australian. When they are having breakfast, you can clearly see the Aussie yellow cabs and Melbourne's tram system. London doesn't have either. They do use the traditional London cab for the journey. The architecture is totally Melbourne, with the verandas and "hotels." Plus the real Crouch End doesn't look at all like this one, even if you allow for the thin spaces.
After the conversation about the lost napkin with the address, in the taxi. We can see a wide street out the side window (over Mrs Freeman's shoulder), but then we see a very narrow, one way street out the front window
Crouch End is an area of north London, in the London Borough of Haringey. It has a postcode of N8 and has a football club called the Vampires.
When Renshaw pulls the gun from the alcohol cupboard, he takes a sip of Jameson whiskey. We can also see a bottle of Chartreuse, and a bottle of Jose Cuervo tequila. The door is a lot more open and the tequila more visible after he readies the gun.
Most modern apartments and appliances have surge protectors built in, so when Renshaw drops the hair dryer in the toilet, the power would not short out.