Angelus: Akuma no Fukuin (MSX2)

Angelus: Akuma no Fukuin
Developer: Enix Publisher: Enix Platform: MSX2 Released in JP: April 1989 This game has a hidden sound test.

After two completely unrelated individuals obtained a mysterious sickness, and a third one started developing those same symptoms in front of him, the London Post reporter Brian Paul is sent to investigate the circumstances alongside his girlfriend Eris, leading them to a world of cults and evil gods.

Sound Test

To access the sound test menu, boot the game while holding T + Return. There is a small dialogue that appears upon entering the menu:

エイミ	アンジェラスの音楽でーす！	Amy	It's the music from Angelus!
美春	うわあーい！早く聴きたーい！	Miharu	Wow! Can't wait to hear it!

(Source: ReyVGM)