Instead of creating a new roar, the crew simply played the original Godzilla roar over loud speakers and recorded the audio.
The "Minus One" refers to the fact that Japan had already been devastated by WWII (brought down to zero), but with the emergence of Godzilla, it puts Japan into the negative. This is reflected in the film's original Japanese tagline, which translates to, "Postwar Japan. From Zero to Minus".
Gareth Edwards, director of Godzilla (2014), attended a screening of the film and described a feeling of jealousy while watching it, stating, "This is what a Godzilla movie should be like."
When asked about the differences between the American adaptations and the Japanese originals, Yamazaki stated that while the American Godzilla is only focused on being monstrous, the Japanese interpretation is both as a monster and as a god. Elaborating, Yamazaki stated, "The point of international Godzilla is that he's a really powerful monster, but a Japanese Godzilla is halfway a godlike creature in many ways. Not necessarily a religious god, but more like a Japanese god, a malevolent and destructive one."
According to Yamazaki, his Godzilla would remain close to the themes of Ishirô Honda's original film, stating, "I love the original Godzilla, and I felt I should stay true to that spirit, addressing the issues of war and nuclear weapons."