Continuity mistake: When Alvin is making the big SOS sign, one shot shows the whole beach and Simon and Theodore are in the middle of the big letter O. In the next shot, they are at the O's edge.
Continuity mistake: Delancy's clothing changes from the old school uniform to the new school uniform then back, when checking Blair Willow's room. (00:51:00 - 00:52:00)
Continuity mistake: In the scene where Linda and Blu are on the computer, when Tulio "communicates" with Blu, the computer is way too much to the right. It reappears when Blu starts squawking.
Other mistake: Grand-Santa has made 70 missions, and Santa (Malcolm) has just completed his 70th mission, totaling 140 years. Yet Grand-Santa is only 136 years old.
Suggested correction: Grandsanta's portrait is shown in the halls of the North Pole with the dates 1902-1941 (with Malcom having done 71 missions from 1941). Therefore he did 39 missions. That makes for a total of 109 years, meaning he was 27 when he took over from his own father.
Continuity mistake: When Rango was at the mayor's office, the mayor grabs out a jug of water, and he opens the lid. But in the next shot, the lid is sealed again.
Continuity mistake: There is a scene where Hugo is on the station and sees a key down on the tracks. There are two separate shots of the key and both times it is buried in the stones next to a sleeper. Then Hugo jumps down onto the tracks to pick it up and its now sat on the middle of the sleeper when he picks it up. (01:22:30 - 01:23:10)
Continuity mistake: At the end of the first film Mumble has lost most of his down, because his bow tie has yellow markings, however in the second movie he has somehow grown his down back.
Continuity mistake: When EB is young and is in the factory for the first time, he picks up some sweets off the factory line. The amount of sweets in his hand then changes between shots.
Continuity mistake: Just before the Smurfs are returned to the Winslows, Patrick consoles Grace. She is wearing black tights under her white dress. Then the Smurfs return on pigeon-back, and miraculously she is now bare-legged.
Continuity mistake: In the scene where Griffin is marketing the yellow sports car to a customer in the dealership, he laughs out loud while fooling around in one shot, and as the camera changes, his face is straight, and when it changes to the previous camera, he is laughing and fooling around again.
Continuity mistake: While Pooh and his hungry tummy are searching for honey Pooh finds himself at Owl's house, and in the first wideshot we can see the wood sign that reads "Dont nock plez ring" with nothing above it, but once Pooh reads the sign suddenly Eeyore's tail is hanging above the sign as a bell-pull. (00:48:25)
Revealing mistake: During the opening musical number, right before Gary joins the large group of people for the dance, he accidentally kicks Walter out of frame. Watch closely though. His foot comes nowhere near Walter when he supposedly "kicks" him.
Continuity mistake: When Tick Tock freezes Rebecca and Cecil, they are in one position, and when they go to the close up of them frozen, they are in a different position. When it zooms back out again they are in the first position. Also, when they are frozen moving on the conveyor belt, they are back in the position they were in on the close up shot. (00:47:50 - 00:48:10)
Revealing mistake: When Tigress is hatching a plan to escape Gongmen Tower after they have been trapped, she looks out over the wall. But take a close look at the archers: they all move in perfect sync, indicating the same animation models were used for all of them.
Visible crew/equipment: When Bernice tells Josh and Rachel to go with Alice so she can talk to Lisa and Stanley, the two red tape marks can be seen on the floor, under the table. (01:29:20)
Continuity mistake: A bear escapes from the zoo and Benjamin finds him in the woods. The bear knocks the gun from Benjamin's hands, then faces him and growls. In the close-up, Benjamin's hair is blowing, presumably from the force of the growl, but in the preceding and following long shots, his hair is motionless.
Other mistake: To get revenge against the reds for chopping off his hat, Benny goes inside the house to use the computer to change the woman's lawn mower order. Benny never hits the 'ENTER' key to complete things. Things are completed when he steps on the 'SPACEBAR'. Same thing happens later when Benny is ordering a female flamingo.
Continuity mistake: When the hurricane hits, you see the "Clearwater animal rescue" sign break apart. After the storm passes, the sign is complete again (albeit missing some letters) on the ground.
Continuity mistake: The protagonist dismounts from the bed, grabs a CD, turns it around. Cut, and the CD is held differently and turned the other way. (00:02:00)