Critical Depth - Secret Characters


To play as Mr. Phatt:
  While fighting Mr. Phatt, finish him off with a combo 
  that does at least 48 points of damage. Once he's 
  unlocked, you can select Mr. Phatt on the Character 
  Selection screen. 

To play as Abaddon:
  Complete the entire game in Captain difficulty mode. 
  Once he's unlocked, you can select Abaddon on the 
  Character Selection screen.