It’s safe to say that “Guardians of the Galaxy” score composer Tyler Bates has never written a cue titled “What A Bunch Of A-holes” before. “That’s James Gunn,” Bates laughs, referring to the movie’s director. “That was in his dialog. It was fun.”

The fact that Gunn named a number of the music cues is a testament to the closeness that Bates and Gunn enjoy after working on a trio of Gunn-directed films together: “Slither,” “Super” and now “Guardians.” They met when Bates scored and Gunn wrote Zack Snyder’s  “Dawn of the Dead.”

The pair’s working relationship is such that Gunn brought in Bates as soon as the director got the “Guardians” job. “He started telling me his thoughts in terms of tone.  He wanted dramatic and thematic,” Bates says. “He asked if I’d be up to writing in advance.” Bates began writing material for the film in March 2013 with Gunn passing along pre-video sequences and often then filming to Bates’ music. The scoring process usually works the opposite way with the composer brought in in during post-production, but when Bates had worked with Gunn on “Super,”  and the director had wanted to film the end of the movie to music, so he similarly had Bates work in advance.

Bates’ early start didn’t give him much of a leg up when it came to the work; the film was constantly evolving as editing took place that would render Bates’ previous work obsolete. “You have a tendency to write and re-write and rewrite,” Bates says as the various bosses have their say. “It’s like trying to paint something on a bullet train. There’s the perception that we have endless resources to create, but they are often times limited as to how many players you can have or how much time.”

The sheer volume and layers of sound that Bates worked with are staggering: “At least half the cues in the movie have more than 500 tracks of audio,” he says because of orchestral passages that are doubled or tripled, choirs, overdubs and other instrumentation. “Everyone’s working with a sense of efficiency because there’s no margin  for error. We had to be calm and methodical.”

The “Galaxy” score, which is out now on Hollywood Records, cover a wide musical terrain from sweeping orchestral themes to crisp battle marches to celestial, dreamy soundscapes. “It was my most demanding score,” Bates says. “I love James dearly, it was paramount to me to make sure that the score was what he had dreamt it would be…like a space rock opera.”

With all the moving parts and the tight deadlines, Bates admits his overwhelming emotion once he finally finished the score was “relief…My team worked 100 hours per week for four months on end.”

Bates’ favorite cute remains an early piece, “Black Tears” — “Only because I wrote it and sent it to James. They were in pre-production. He called me and he was emotionally moved by it. Those are the moments you show up for,” he says. “This idea had just gown into something and it now has a life. It was establishing a piece of the musical language of what the film is about.”

Not content to have Bates score the movie, Gunn insisted that Bates, who has also scored such films as “300,” “Sucker Punch,” “Watchmen,” and “The Devil’s Rejects,” appear as an extra in the film. “Within three minutes” of getting to the British set, “someone from makeup grabs my hand and 40 minutes later I have dreadlocks and s scar,” he says. His scenes lasted for a day and a half. “It was cool for a minute, but after six hours of standing around,” he admits he was ready for his acting career to end.

While he doesn’t have many comedies on his resume, Bates has written scores for a diverse number of films. One that resonates the most to him personally was Emilio Estevez’s “The Way,” which chronicles a man’s journey as he walks Spain’s sacredEl Camino de Santiago. “People couldn’t believe I did that,” Bates says, “but that’s my natural headspace, that score, when I’m just thinking.”  Instead, he jokes, people think “I’m sitting around watching torture movies with Rob [Zombie] all the time.” When, in fact, he adds “I found the whole content of ‘Devil’s Reject’ to be abhorrent. I was thinking ‘Holy hell, this is fu**ed up.’ It was totally disturbing. It’s what Rob intended to do.”

Bates is a bit of a musical every-man and for his palate cleanser following “Guardians” release, he’s headed on the road as lead guitarist with Marilyn Manson to play the European festival circuit. He met Manson after the shock rocker appeared on season six of  “Californication,” a show Bates scored for all seven seasons. That meeting led to Bates writing and producing Manson’s current album.

“Films make me completely neurotic,” he says. Going out on tour and hitting the stage “gives me an energy that I can take to the next movie.”