This is an easy way to get the songs on DDR SuperNOVA: Instead of trying to fully complete 100 or more% of each stellar joint, only complete the 1st showdown and you'll get all the songs from that specific joint. This works on all joints exept "Nitro" and "The Last". To get songs from them, you have to complete the EX Showdown. There are more songs in the secret "Pizza Box". To get it, complete every single trial and showdown. It has many more songs in it. (And I DO mean MANY!!!!)

Enter,
X,x,x,x,up,down,right,left,
And you will have Max 300 in game mode.
IT IS ALSOME!!!

At the Main Menu Enter
up,left,down,right,up,left,down,right.
You will have all songs and dancers.
To disable enter code again.

It has been rumored that there are 5 ultra secret songs only playable on the Online Mode in DDR SuperNOVA. They are:

Feelings Won't Fade (Extend Trance Mix) - SySF
HONEY PUNCH - Riyu Kosaka
Nijiiro - DJ YOSHITAKA feat. G.S.C. License
Silver Platform ~I wanna get to your heart~ - U1 w/Leah
Trim - Kobo (10 foot Heavy song)

Play on the Online Mode featured in DDR SuperNOVA to find out if this rumor is fact, or fiction.