COURSES!

Start completing courses (doesn't matter what lifebar you are using) and you'll get more to buy in the shop. The last courses are Boss Rush courses which are HARD to complete for several reasons:

-You cannot set modifiers
-You must play at 1x
-The last song in the course is one of the game's boss songs on CHALLENGE difficulty, which is coincidentally the one you want to unlock

Boss Rush 1 offers MAX 300 (Super-Max-Me Mix)

Boss Rush 2 offers Chaos

Boss Rush 3 offers Fascination MAXX (Healing-D-Vision is here but it is only on Heavy)

Boss Rush 4, the HARDEST course of all, ends with Fascination ~eternal love mix~. Healing-D-Vision is probably unlocked here instead of BR3 because it is on Challenge as well. Beware: This course is made up of ALL the 10-footer songs in SuperNOVA with the first three coming back from the first 3 Boss Rushes in Heavy while the 3 you've yet to see show up on Challenge. Therefore, the course is longer than the others and you have even less room for error than what is allowed in the first three Boss Rushes at the end of the course. Because of how BS Healing-D-Vision and Fascination are, you're very likely to fail.

If you're having trouble clearing Stellar Master Mode Trials that require you to clear a certain number of consecutive songs with a male or female dancer, do this: When you get one song done, exit and save your game, then return to where you were to continue the trial. If you do not get the right dancer, reset your PS2 (not the game) and try again. You will not lose your prior progress whereas you normally would otherwise.

If you're like me and have the crap plastic pads, stack them one on top of the other and turn on two player mode. This way you'll effective double your points as you dance for both player one and player two. Some of your steps may not reach the bottom pad but it's still effective enough that it wont kick the bottom pad off.
It's also an effective work-a-round in Stellar Master Mode to meet conditions lke turn on Sudden or Dark, ect. Make the changes for the top pad since its score is what counts and just leave the bottom pad alone. Then ignore the top pad's display and just watch the bottom pad's.
Just be sure not to dance too crazy or you'll mess up the alinement for the pads. You use duck tape if it's a real problem for you though.

Bored? Just play the Game Mode version repeatdly and you'll get points like it's nobodies business. 20,000 points is an easy thing to get in less than an hour. Good luck.

When dancing on the mat, keep your feet off of the middle. Only move them when you need to go to the next step. It is soo much easier to complete difficult, expert, and challenge songs.

Now that SuperNOVA revived Extra Stage, you can now do a bit of speed-unlocking.

To get an Extra Stage, make sure your last song is on Heavy in Game Mode and that you beat it with a grade of AA. SuperNOVA has toned down the rediculous "Full Combo needed for AA" scoring system of EXTREME and EXTREME 2 and now gives you a bit of leeway. Of course, you're going to want to have a ton of Marvellous/Perfect steps and as few Greats and zero of the rest.

Another method of gauging yourself is that if you can get 95,000,000 points or higher, that is an automatic AA. That, and you'll hear an obvious warning klaxon at the results screen after your last song.

Here's the songs for each difficulty:

Easy - MAX 300 (Super-Max-Me Mix)
Medium - Healing-D-Vision
Hard - Fascination MAXX
All Music - Fascination ~eternal love mix~

All songs are played with the following modifiers: x1.5 (arrow spacing), Reverse (arrows scroll DOWNwards), Rainbow (gives you a chance to identify the notes).

All of those songs are a pretty accurate representation of the difficulty of the song...compared to the OTHER 10-footers. Healing-D-Vision is the easiest to beat however.

If you can beat the song (at least with an A; the lifebar probably drops too much to get anything lower), congratulations! You have enabled the song to be listed AND purchased from the shop (all boss songs are 20,000 points).

AND, if you manage to get yet another AA, you get the Encore Extra Stage:

Encore Extra Stage: Chaos

No screwing around! One misstep on the Encore Extra Stage is an instant failure. Chaos is played without ANY modifiers and that's the only thing against you since it's littered with approximiately 42 stops.

Failure to beat any stage merely results with the game taunting you by simply LISTING the song in the Shop, *unavailable* for purchase.

For this cheat, you need to have at least 10 EX VIP Cards, and 9 Diamond EX VIP Cards in every Stellar Joint (all except THE LAST, which you can't unlock the Diamond EX Showdown). Once you do, head over to THE LAST, and complete 10 Trials (there are 11 Trials, but you need 10 for this). One you have completed the 10th Trial, you should have a message saying that you can complete the Diamond EX Showdown for THE LAST. If you do, CONGRATULATIONS! You have unlocked THE LAST Diamond EX Showdown! However, you still have to complete it. If you have the Diamond EX VIP Card, and you have the other 29, then you have unlocked PIZZA BOX. Hooray!

To unlock the "boss songs" via Stellar Master Mode instead of Game Mode, clear these stages:
Fascination Maxx: Complete "The Last" EX Showdown
Max 300 Super Max-Me-Mix, Chaos, Healing-D-Vision: Complete "Nitro" EX Showdown

You will need 2 controllers for this trick...if you're having trouble completing the Phantom Stellar Joint's 9th Trial (Turn on Dark and Hidden only and do a Full Combo on Expert or Challenge), try this: Plug in a 2nd controller, then select these Options for Controller 1 (assuming you'll use that side) but do NOT choose the options for Controller 2. Choose the song you want to play, then watch the side you're not playing...in other words, if you're Player 1 here, play as if you're playing Player 2's side. Use the arrows there as a guide to hopefully get a Full Combo-even though that unused side fails, if you clear the song on your side (with Dark & Hidden on) with the Full Combo, it counts as clearing the Trial! This can also be done with certain other Trials you may be having trouble with.

To unlock the character Glow for purchase in the Shop (costs 5000 points to buy), clear the Glow Stellar Joint Showdown level in Stellar Master Mode.

To unlock Endless, Survival, and Combo Challenge Modes for purchase in the Shop, win all VIP Cards in Stellar Master Mode (except Pizza Box VIP Cards) and purchase all unlockable songs from the Shop.

To unlock the hidden PizzaBox World, collect all the VIP Cards in Stellar Master Mode.

To unlock the character Pop Corn for purchase in the shop (costs 5000 points to buy), clear the Popcorn Stellar Joint Showdown level in Stellar Master Mode.