Pizza Diskarmer
Clear game on any difficulty to unlock Pizza Diskarmer. To activate, hold L1 on the Tecmo screen until it fades away.

Unlock "One-World" Mode
Clear game on any difficulty to unlock One World Mode.

Unlock Easy Mode
Die three times to unlock Easy difficulty mode.

Unlock Hard Mode
Clear game on normal to unlock Hard difficulty

Unlock Legendary Mode
Clear Hard mode to unlock Legendary difficulty.

Unlock Udon Armor
Complete Level 30 Necromandio Cave on Legendary Difficulty. Hold L2 on the Tecmo screen until it fades.