Forever Fantasy has translated Famitsu's Dissidia Final Fantasy gameplay impression posted this morning in the magazine's website:
DISSIDIA FINAL FANTASY
Planned Release: December 2008
The [Dissidia} demo units had selectable difficulty modes, a "Light Mode" for beginners and a more difficult "Hard Mode". The two difficulties played very differently, with even the same character having different usable skills. It looks like you will be able to customize and change the skills. As for the playable characters, [Final Fantasy] 1's Warrior of Light and Garland combination return from the previous playable demo, then we have 10's Tidus and four Onion Knights from [Final Fantasy] 3. The Cloud of Darkness and Jecht were unfortunately not playable, but we can confirm they did show up as enemies.