Unlock Ultimate Mode:
Complete the story. You begin the game with Zangetsu and already have all the bonus abilities unlocked for killing Miriam, Alfred, and Gebel. In Ultimate mode the bosses are enhanced, with new attacks and more health.
Unlock the True Ending:
Complete Nightmare Mode to get the True Ending.
Unlock Nightmare Mode:
Complete the story. You will have Miriam, Alfred, and Gebel available from the first level (no Zangetsu). In Nightmare mode the bosses are enhanced and gain new special attacks. The last level is totally different and you will face a new last boss.
Boss Rush Mode Modifiers:
Once you have unlocked Boss Rush mode you will be able to hold the following buttons while selecting the 'Boss Rush' option to activate the corresponding modifier(s). If you have done it correctly you will hear a confirmation sound. Note: It is possible to activate more than one modifier at a time.
HP and WP refill after each battle.
Infinite weapon points.
Ultimate Zangetsu (Full-Powered).
Unlock Boss Rush Mode:
Once you have unlocked Nightmare mode and Ultimate mode you will automatically gain access to Boss Rush mode. In Boss Rush mode you will be able to control ALL four party members and a selection of their subweapons. Only one subweapon per character per fight can be quipped and Zangetsu does not have any of his special abilities from the Bad Ending route.