In a psychological way, Majora's Mask was darker. You're in a constant state of panic in a town where most of the people are in denial that their lives will end via the moon crushing them in 72 hours, where the music gets creepier by the day and death is such a vital theme to the entire story in every chapter. You constantly feel anxious and helpless empathizing with the people of clock town and the other provinces, the fact you can't save everyone within those 3 days also gives a sense of sadness and grief. It's honestly unbelievable Nintendo wrote and created Majora's Mask within a year, that game is a true masterpiece and sets the disturbing mood better than most rated T/M games I've ever played/watched.