In the original Back to the Future, Marty McFly tends to get carried away while playing his guitar, causing confusion and/or disapproval from any nearby squares.
The examples given of his overzealousness are:
- In Doc Brown's lab when he blew the speaker
- During the audition for his school's dance
- During the performance for his parent's school dance
According to Michael J. Fox's IMDB page, he
Received his first guitar for Christmas when he was 8. He taught himself how to play.
Given MJF's experience with playing guitar, was the shredding in the film of his own composition? If not, did he have any input on what his character would do in those situations?