Continuity mistake: In the episode with Alex at the art museum and Justin a teacher's assistant, as Alex is in the room with all the paintings, she puts a piece of rope around the door handles. Later on when Alex says, "Go ahead scream panic," we see Alex in front of the door, but the rope is gone, but the next time it shows Alex the rope is there again.
Continuity mistake: In the "Wizards vs. Werewolves" special, just as the Russos learn that Alex and Mason have gone to Transylvania, Max is playing on his Nintendo DS. He then flips it shut. The shot switches to Justin, Jerry and Teresa. They talk and the shot switches back to Max, and you see him flip the Nintedo DS shut again.