Continuity mistake: In the scene in the Beatles hotel room where Nancy Allen comes out from under the cart with the cokes on it, when she first sees the Beatles' guitars, notice that in the very first scene, the Hofner bass is left handed (the pick guard is on the left as you're looking at it), then it cuts to her, then when it cuts back to her rolling on the floor with the bass, it's suddenly right handed, then when in the last scene with her handling it, it's left handed again.
Continuity mistake: When Cheech is turning over his car to pick up Chong you see him starting to turn over before he reach Chong. When it cuts Cheech has passed Chong before turning over. (00:07:40)
Factual error: When Buddy and the musicians tour bus is towed to the Clear Lake Auditorium for the final concert before the fatal air crash, the canopy states that the concert is on the 3rd of February. The fatal accident that took Buddy, The Big Bopper and Ritchie Valens occurred at 1am on 3rd February 1959 so the canopy should have read 2nd February.
Audio problem: Near the end of the film, when the Commodores finally go on stage with their equipment, Bobby Speed announces them from inside the control booth. But the movement of his mouth does not match the audio (you have to look at his reflection in the glass wall).
Continuity mistake: Throughout the whole film you can see that Rick Danko's bass playing has been completely redone. What he's playing and what you hear are completely different things.
Visible crew/equipment: When Gene is on top of the coaster at the amusement park, you can see a cameraman below filming.
Factual error: In the sixties retro scenes vehicles can be seen that didn't start production until the seventies.