Continuity mistake: When Mr. Perkins is looking at a picture of him and Vector, he sets the picture frame down. In a few shots, the frame disappears.
Continuity mistake: Edith disintegrates Agnes's unicorn and a pile of ashes is left on the ground. In two shots, the pile of ashes moves slightly further from Agnes.
Continuity mistake: After Dr. Nefario uses the fart gun on a minion, the minion falls off the table after being knocked out. Several shots later, the minion is gone without getting up and moving.
Factual error: When the little boy drops his ice cream on the ground and Gru makes him a balloon dog, notice that the dog's ears are not connected to each other. This would be impossible to make unless you used two balloons, but it only showed Gru using one.
Continuity mistake: When Gru gets shot with all those guns at the end of his attempts to get in Vector's house before he first sees the girls, his goggles are at the top of his head. After he gets shot, the dust is not over his eyes, indicating that his goggles were over his eyes, shielding them from the dust.
Continuity mistake: The car was parked a few yards outside Vector's house. The girls leave after delivering the cookies and they are half way down the path. Yet a minute and 45 seconds later, they are still walking back to the car even though it was only a few yards away from Vector's house.
Continuity mistake: When Gru enters the bank, the glass wall that the banker is seen behind is a type of glass that you can hardly see anyone behind. The next shot shows a glass wall that you can see the banker behind.
Continuity mistake: At the assembly, Gru shows everyone the Vegas Statue of Liberty. It wasn't there any shot prior to this.
Audio problem: In the scene where Gru grabs Edith while trying to get the girls to sleep, we can see Agnes laughing out loud while jumping on her bed, the sound of her laughter does not synchronize with her mouth.
Chosen answer: It is not very difficult to hold a straw between one's teeth, or gums and speak at the same time. A coworker of mine does it all the time with a pen.
MasterOfAll