Continuity mistake: A penguin uses binoculars rotated at a 90 degree angle, but the shot of the view through them is composed as if they were being used normally (horizontally level).
Continuity mistake: When the penguins disguise themselves as a snowman, the nose of the snowman is a penguins beak. After they bump into the elevator, there is a carrot lying in the pile of snow. But the carrot was never part of the disguise.
Continuity mistake: When the penguins burst through the window, shards of glass completely cover the whole floor. In the next shot all the glass has completely gone.