Select cutscenes replaced by FMV, the Judgement Ring is increased in size, more subevents, monsters and items. 2 bonus dungeons, and you get to play as the final boss characters in a party in the a subevent dungeon.
Sounds awesome, and the game supports all JP saves from the original so you don't have to replay to get the extra stuff. Bebpo says there's a full cutscene theatre with all realtime+FMV scenes in the original and so you'll probably be able to just view the new FMVs this way.
I think the attack is named "Iron Claw" (aian kuro), may be Lenny will kick the guy's butt to the enemy to attack, using the Iron Claw member as a human weapon.
There's a page up on the official site now. There's no Japanese text support on this computer, though (it's not mine), so I'm not sure if there's any new info on this page. But here it is: