Jump Festival is a Japanese event of Shonen Jump Magazine and Square enix have the biggest stand there. The event will be at 22/12 - 23/12.
The public will be able to play Dragon Quest: Monster Battle Road for arcade and Final Fantasy IV for DS.
If you have Dragon Quest IV for DS, you can receive a visitant at your "town", but for it, you must be at chapter 5 at least.
The others games Square Enix will show in video, here you can see the list;
Chocobo's Mysterious Dungeon (Wii)
Final Fantasy Crystal Chronicles (WiiWare)
Final Fantasy Dissidia (PSP)
Kingdom Hearts 358/2 Days (DS)
Kingdom Hearts Birth By Sleep (PSP)
Kingdom Hearts Coded (mobile)
Fabula Nova Crystallis Final Fantasy XIII (PS3)
Final Fantasy VII Advent Children Complete(Blu-ray)
Star Ocean First Departure (PSP)
Front Mission 2089 Border of Madness (DS).
Check details at Square Enix