Romance is discussed, and there's some light flirting.
Violence & Gore
None
Most violence is comical, but later gets slightly harsher with minimal blood.
Profanity
Moderate
Shit, fuck, dick, slut, and cock are used sparingly alongside lesser profanity like ass.
Alcohol, Drugs & Smoking
Mild
Adults are seen socially drinking, sometimes resulting in intoxication. Retsuko herself gets drunk on one occasion. However, the consequences of this intoxication, such as bad hangovers/affecting of work performance and memory are realistically depicted.
Frightening & Intense Scenes
Mild
The death metal sequences can spook younger audiences, especially since most of them come out of nowhere.