It might be a little late to put this up since Lumines II has been out on the market for months, but the official Japanese site for Lumines II just released a free downloadable demo. To play the demo you need to:
1.) Save the file to your hard drive
2.) Open the GAME folder in your PSP memory stick
3.) Make a new directory called ULJM05232
4.) Copy the EBOOT.PBP file for Lumines II in the directory
The demo only comes with one skin and it isn’t Heavenly Star. So why bother with it? It’s a small, under 10 meg, file that you can keep on your memory stick in case you want to play a quick game of Lumines.