The Happiness of the Katakuris

The Happiness of the Katakuris at IMDB

Remember how they called Shawn of the Dead "a romantic comedy with zombies"? Happiness is a Japanese musical with zombies. The cover photo with the Sound of Music line up and a shot from the main zombie dance number superimposed over the sky predates Shawn by several years.

Final thought: but the love interest in Happiness is a con-man