Continuity mistake: The king's youngest daughter climbs down a wall and drops a tightly sealed Erlenmeyer flask (invented centuries later) filled with a toxic potion. The flask is full when it is dropped, but partly empty after it has been caught and handed back to her by her spouse's earlier visitor.
Plot hole: The Polar Bear King (human version) is held hostage at the witch's castle. When the witch comes to pay him a visit in his cell she unlocks the door very elaborately. It is very surprising that the witch is not surprised at all that a) one of her subjects is inside the cell advising her captive on an escape plot and b) that this subject made it through the locked door.