Complete Stage 5 of Arcade Mode (any difficulty)

Complete Stage 2 of Arcade Mode (any difficulty)

Play Ranking Mode in Arcade Mode (hold down P+K+D+START button during Attract Mode)

Use Dural in Arcade Mode or Offline Versus (In Ver.2.1 hold START button when selecting a character)

Win a round by ring out in Arcade Mode (any difficulty)

Select game settings in Arcade Mode while holding the □ button to enter Attract Mode

Enter ↓↓↑↑←←→→ at the character select screen in Arcade Mode

In Blood of the Dead, kill the Warden with the Blundergat, Acidgat, and Magmagat in a single game

In IX, acquire Serket's Kiss

Get gnawed by 5 rats at the same time

Defeat the Prison Governor without being hit by a sniper

Complete a level without taking any Nekro

Use the Totem of Undying to cheat death.