To unlock the minigame "Pure White Giant Glastonbury", beat the Rank 04 battle. To play it, go back to the motel and select your TV. The game can be played from there.
"Real" Ending
To see the true ending, complete the game with all beam katanas obtained. If you do not have them all by the end of the game, choose to return to Santa Destroy, obtain them, and return to a bathroom to view it.
Complete the game and after watching the whole credits you can make a new save. After that you can select the Bitter difficulty along with your old equipment.
