It would appear that the trial is now up:
http://07th-expansion.net/rose/trial.htm
EDIT: I've uploaded a Mac-compatible version:
http://jumbofiles.com/nzxwb2anav3k
The website I uploaded to has misleading adverts, so here's some screenshots showing which links to click:
There's also that bug where you have to click the screen before the game will load.
EDIT2: And here's some tweets RedKey sent me, which might be helpful for figuring out what to do in the fighting minigames:
"defense: put your mouse over flashes. attack: click on flashes three or more times, then right click and try to pick the best card"
"if in a fight you always choose the highest-value card you get Straight Flush bonus. If you manage to always hit, that's Sharpshooter"
"Overkill: attack 4+ times before picking a card; Juggernaut: perfect defense"