The song "Angel of Death" by Slayer was originally cleared to be included in the game, but was removed because of the song's controversial lyrics. Metallica pressed on for Slayer to be in the game and "War Ensemble" was cleared at the last minute.

"Slayer's got to be part of any heavy metal video game. There had been some issues with their lyrics. That gets into a whole slew of stuff like, 'Microsoft won't do it if this lyrical content is in there.' There's all this bullshit you have to deal with, but we stood up for Slayer, and we finally got Slayer cleared like a week ago." "“ Lars Ulrich, Metallica Drummer
Contributed by Pogue-Mahone
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When the box art for Guitar Hero: Metallica was revealed to the public, the cover misspelled the band name Lynyrd Skynyrd as "Lynyrd Skynrd". The spelling was corrected before the game was released.
Contributed by Pogue-Mahone
The Career storyline about a band following Metallica on tour as an opening act is based off of a true story.

"There were some guys in a beat-up old van and they were following Metallica all over Europe, everywhere they went on tour. And then they wound up hanging out with the crew and the crew would feed them. And then eventually Metallica let them get up and open for them." - Alan Flores, Lead Designer
Contributed by Pogue-Mahone
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King Diamond's makeup and necklace had to be changed in the game to exclude any Crosses, as to make sure that nobody would be offended. King Diamond made the changes on his makeup and necklace himself.

"Upside down crosses on the face was not quite acceptable. Actually, any kind of cross painted on the face might have had a sense of 'blasphemy' to some of all the business partners involved in this big venture. The same goes for the upside down cross necklace." "“King Diamond
Contributed by Pogue-Mahone