Simplify the following text for a Grade 10 native English-speaking person.
Original: Nintendo of Japan made a 60-minute anime ( Japanese cartoon ) film starring Mario and his friends in 1986 , but this film has never been shown or sold on DVD outside of Japan .
Simplified: Nintendo of Japan produced a 60-minute anime feature which starred Mario and his friends in 1986 , although this film has never been released outside of Japan .