Sander Stolk is poised to release a new version of AmplituDS soon. I have had the pleasure of play testing this and can say it is coming along very nicely. There are some features that have been added that I am told fans of the PS2 version will appreciate.
The next release will feature power-ups, multiple difficultes, 2 stages and most importantly FAT support which I can personally confirm works a treat on SuperCard. You will also be able to add/insert your own custom tracks as previously planned.
I created a couple of videos along with some screen shots for Sander of the gameplay of both of the music tracks. I will post the videos in the comments or you can find them on Sanders homepage along with the full selection of screen shots.