Originally Posted by pentarou
Accidentally unlocked some kind of secret song
while on Stage Select mode.
If anyone figures out how to reliably reproduce this, let me know. This is Stage Select on Maniac/Normal with Palm/Abnormal; I was choosing several different stages before I ended up on Stage 5, so I figure I must have hit some kind of combination. I haven't been able to unlock it again since.
I found this on doing a google search and it works:
Unlock Alternate Stage Music
At the 'Level' select screen tap levels 4, 1, 2, 3, and 5 in order. You will hear Reco will say 'Bikkuri shita' when level 5 is tapped if you have entered the code correctly. When you now select any level the song 'Kin'iro no Hoshifuru Utakata no Yoru ni' will play instead of the normal stage music.