Tales of the Abyss Cheats

After completing the game and saving after the credits, load the cleared Save File. It will have a star on it. You will be able to access the Grade Shop where you can buy extra stuff that affects your next game with the Grade Points you received from battles. Any leftover grade will be kept for your next playthrough.

In order to unlock this secret shop, you must have completely filled out the collector's book in the game(which requires two playthroughs) Once completed, speak to the man dressed in purple at the library in the Daath church to receive Jade's "Item Collector" Title. Speak to the man again with the title equipped and the shop will appear near the inn in Grand Chokmah.

The Abyss Replica Facility is a secret dungeon that can only be unlocked when you are playing on your second playthrough. To gain access, you need to have saved Shiba and completed the Ortion Cavern(East) side quest. Go to Sheridan and talk to the two men in the northwest part of town, then Shiba, and you will at last be taken to the dungeon.