Revealing mistake: During the bedroom scene with Felicity and Fat Bastard you can clearly see the air hose that fills his suit when he rolls over in the bed. (00:49:10)
Revealing mistake: In the scene where Mini Me is drawing the goodbye card to Scott, (before they go to the moon) you can see that the drawing is already on the page and Mini Me just traces it over. (01:05:50)
Revealing mistake: In the scene where Ms. Spitz is with Austin at the party and she orders the hitman to use the bazooka, you can clearly see when he fires that the missile stays in the tube. (00:28:15)
Revealing mistake: When Austin pounds on the glass tube, it's easy to see they are three separate panels of glass, rather than being sealed. Therefore, the gas inside could have escaped.