Audio problem: When Indy confronts the butler at the castle, we hear the butler say, "If you are a Scottish lord then I am Mickey Mouse." But his lips say something else. He actually said "then I am Jesse Owens." This line was changed because they thought that a lot of the audience wouldn't know who Jesse Owens (the black athlete who won at the Berlin Olympics) was. (00:46:00)
Audio problem: When Doc and Marty return to the year 1955, you hear the squealing sound of tyres braking heavily, but the DeLorean is flying. (01:02:25)
Audio problem: When Gwen is getting hit on by the drunk guy who says "nice outfit", the lines for both drunks have been poorly dubbed over and don't match their mouths.
Audio problem: When the crew are running around the passages, a guy with a beard yells something at Bud, and then uses a fire hydrant to put out a small fire. Funny, it doesn't make a noise.
Audio problem: When Russ jumps from out behind the bush and says, "I say that ant is ours", his mouth doesn't move.
Audio problem: At the Video Armageddon shortly after the event host first realises Jimmy isn't there, the female voice counting down the time proclaims "...the Video Armageddon will commence in T-Minus two minutes and counting". However, the digital timer on the stage is at precisely 01:00, not 02:00. (01:21:15)
Audio problem: When Bond takes the 'belt' off his tux, in order to get the concealed rope, there is a scratching sound, as velcro ripping. But the belt is not closed with velcro. We can see metal clamps when the belt lies on the ground and Bond removes the rope.
Audio problem: When Bill, Ted and the other historical figures are getting Sigmund Freud into the phone booth, in a shot shown from outside the window looking into the booth, Freud says "What are you doing", but his mouth isn't shown moving along with the line. (00:47:13)
Audio problem: During the fight with the Scoleri Brothers, Egon warns doctor Stantz about the sudden apparition of the ghost coming through the wall. He yells "Behind you, Raaay!", but in the close-up Harold Ramis' mouth is not uttering "Behind you." (00:35:50)