When the Pevensies are outside their treasure chamber in Cair Paravel, Peter tears off the entire bottom of his shirt, which would not have worked with a button down shirt because it splits in the middle, to make a makeshift torch. After Edmund takes out his flashlight, the camera once again shows Peter. The missing piece of his shirt is only on the right side. The rip changes again when they are entering the vault
Near the beginning of the movie when the children are saving Trumpkin they come up to the lake on the beach. The soldier's boat is in the middle of the lake. However, when Peter jumps in to save Trumpkin he jumps right above when he is thrown in and not from the shore.
While the Pevensies are riding in the boat with Trumpkin, Lucy's hair looks matted, but when they get out of the boat her hair is sleek and neat.
At the beginning when the children are transported to Narnia on the beach, they are at first inside a cave. They run out of the cave onto the beach and start taking off some of their clothing to play on the beach. When the shot shows them from the other angle, the cave is now filled with water because the tide has come in to flood it - in just 5 seconds.
When the Telmarines are about to throw Trumpkin in the river, Susan shoots an arrow that lands near the rear of the boat below the steersman. As the camera angle changes and the arrow is now more toward the front of the boat, under the rower.
When the catapults are being built (at about 00:46:40), there is a two-person saw in use. In actual use, the worker "in the pit" below the log being cut should be covered in sawdust and wood shavings. However, the actor in the shot is clean.
When the catapults are being built (at about 00:46:40), there is a two-person saw in use. In actual use, the worker "in the pit" below the sawn log should be covered in sawdust and wood shavings. However, the actor in the shot is clean.
The number of arrows in Susan's quiver, fluctuates in many scenes. It's a magical, automatically refilling quiver made by Father Christmas, as per the previous movie.
The children play on the beach upon first returning to Narnia, then are in Cair Paravel in the next scene. The wetness and position of their clothing is different, but that is because much time has passed.
When the bear charges Lucy on the beach, Trumpkin seems to pull a bow out of nowhere. However, when Susan nocks an arrow to shoot the bear, Peter, Edmund, and Trumpkin are clearly seen running to the boat to grab weapons. It's entirely feasible that Trumpkin found the bow and arrow in the boat.
It's impossible for the soldier to catch up to Lucy. She wears no armor and weighs significantly less than the soldier in full metal armor. However, one would not be a good tactician, as the Telmarines thought themselves, by having just two riders going after them. These new two soldiers may have been patrolling, waiting for someone to try and make a break for it.
(at around 40 mins) In the scene where catapults are being built, there is a two-person saw in use. In actual use, the worker "in the pit" below the sawn log should be covered in sawdust and wood shavings. However, the actor in the shot is clean.
During the castle raid, Reepicheep's mice scuttle down a wet corridor where a torch is hanging. The water shows the reflection of the torch but not that of the mice.
Around one hour and 20 minutes into the movie, Edmund and his griffin are flying over the aftermath of the castle courtyard battle. At one point, Edmund's head becomes transparent. This reveals the use of a green screen.
The final battle has automated "catapults" launching ton-boulders every few seconds, yet seem to be powered by at most a handful of men on cranks, which is grossly insufficient.
At the beginning, when Susan picks up a magazine from the news stand, it is apparently a December 1939 edition magazine. This is not possible, as the Pevensie children were evacuated to the countryside at the start of the previous movie, which (as it featured an air raid on London) could not have happened before September 1940, and it is quite clearly summer during the scenes at Professor Diggory's house. A few minutes later Peter mentions they've been back from Narnia for a year, meaning that it is at least May 1942 now.
In the beginning of the movie, the tube station that the Pevensie are waiting in when they are transported out of London and into Narnia is Strand. This station was closed from 1940 to 1946 for use as an air raid shelter.
In the scene where the Pevensies open their chests after returning to Narnia, Peter's chest has a large rock on top of it. However when he opens the chest no falling rock can be heard.
When Caspian enters Miraz's room at night, during the castle raid, the camera pulls out to a shot where Caspian is standing over Miraz in bed. A camera shadow is visible on Caspian's shoulder.
When escaping the castle, Caspian and Peter and the Professor were on horseback. When they are approaching their niche hideout, they were walking with no horses in sight in the background. What happened to the horses? (The girls used the big Friesian horse to escape the hideout to look for Aslan.)