Continuity: When Conrad first puts the spider lock in his pocket it is put in his left pocket, but when he takes it out, he takes it out of his right pocket.

Continuity: At the end of the movie when the Cat finished cleaning up the mess and was packing Thing 1 and Thing 2, everything looks immaculate except in one scene, in the corner of the living room, there are still purple splashes.

Continuity: Right after the Cat, Sally, and Conrad crash, Sally's hair bow is half way down her pig tail. In the next shot, it's back on top in a perfect bow.

Continuity: In the scene when the Cat is with the kids in his car, right after they show his new steering wheel being a chain linked one, the next shot shows it as a regular steering wheel, and then back to a chain linked one for the rest of the scene.

Continuity: When thing one and thing two come and they start messing everything up, they get the cupcake mix from the previous scene on Sally and Conrad, but in the next shot it's gone.