It is available at first as a song for the Encore Extra Stage, when a player gets an AA or higher on Kimono Princess.
The song has 4 versions, and when a player selects the song for his Encore Extra Stage, 1 of the 4 versions are randomly chosen for the stage. But when one version is cleared on Encore Extra Stage, all versions are unlocked.
Upon its release, faithful gamers of DDR have been striving to unlock it because it sounds so classic and cool and everything else that a DDR fanboy loves about DDR songs.
Ver. A - runs at a constant 170 BPM. Has a rather hard stepchart, though not comparable to Fascination ~eternal love mix~
Ver. B - the easiest of the 4 versions because it only has 170 BPM gallops in the middle part and not streams. Slows to 85 BPM before the gallops part.
Ver. C - irritating step patterns on the middle part. Given with some stops and slows, it can throw players off. Also, it's harder than A, but not harder than D.
Ver. D - more streams and gimmicks (like stops similar to CHAOS and Fascination ~eternal love mix~) than Version C, it is possibly the hardest version.
Guy 1: Yeah! Full Combo on Kimono Princess! Now let's beat that roppongi EVOLVED!
Guy 2: I hope it's Version B, so we can unlock it already!