Continuity mistake: Evelyn is reading the instructions for the transition. Item 4 says "Don't forget to breath." When she reads them again prior to pressing the green button, the note now correctly says "Don't forget to breathe."
Other mistake: In the hot dog finger universe, everyone uses their feet for dexterous things, like playing the piano...but the pianos themselves are still designed exactly like our universe, at waist height where it's convenient for playing with hands, but very uncomfortable to play with your feet.
Continuity mistake: When Evelyn is fighting the girl with the dog in the office, the dog changes color when it gets kicked, likely because it's a fake dog.
Continuity mistake: The instructions Evelyn is given had two copies created for the film - the handwriting and circling of the numbers change between shots when she's reading them in the IRS office. Notably the first time we see the instructions it says "don't forget to breath" at the bottom, then later that's changed to "breathe" as it should be. Although interestingly that change is the only one on that version of the notes, implying someone caught the grammatical error during filming and added the "E."
Other mistake: When Evelyn becomes a rock, the other rock says they are in a universe where the conditions weren't right for life to form. During this scene, insects are visible flying and moving across the frame, and a grassy plant is visible in the lower right. These would not be present in a universe where life could not form. (01:41:06)