[Enja Hamman]

The Game Gear version of Aa Harimanada has an unused theme in it, which is exactly the boss theme from Doraemon: Noranosuke no Yabou.
When I mentioned this to Masayuki Nagao he said

Doraemon’s and Harimanada’s tunes are created at the same time in the same room of the sound brunch and I was a chief of sound crew. so… thinking…