The Grim Adventures Of Billy And Mandy

Play as Chicken:
Successfully complete Story mode as all characters and accumulate 10 hours of gameplay.

Play as Eris:
Successfully complete Story mode as Billy, Mandy, Grim, or Irwin.

Play as Fred Fredburger:
Succe.ssfully complete Story mode as Billy, Mandy, Grim, or Irwin

Play as Hoss Delgado:
Successfully complete Mission 9 in Tier 1 in Mission mode.

Play as Mogar:
Successfully complete Story mode as Billy, Mandy, Grim, or Irwin.

Play as Nergal:
Successfully complete Story mode as Billy, Mandy, Grim, or Irwin.

Play as Nerglings:
Successfully complete Story mode as all characters.

Play as Vikings:
Successfully complete Story mode as all characters and destroy every letter in the credits sequence.

Alternate costumes:
Successfully complete Story mode with any character to unlock an alternate costume for that person.