Antinomy of Common Flowers

Unlock Extra Colour Palettes:
When you complete Story mode an extra two colours become unlocked.

Silver Colour
Complete Story mode on any difficulty.

Gold Colour
Complete Story mode on Overdrive difficulty.

Unlock Joon Yorigami (Pestilence God):
When you beat the second Story mode mission that has Marisa Kirisame paired up with Koishi Komeiji this hidden character will become unlocked.