Alternate costumes:
Successfully complete Story mode with any character to unlock an alternate costume for that person.
Play as Chicken:
Successfully complete Story mode with all characters and accumulate 10 hours of game play time to unlock Chicken.
Play as Eris:
Successfully complete Story mode with Billy, Mandy, Grim, or Irwin to unlock Eris.
Play as Fred Fredburger:
Successfully complete Story mode with Billy, Mandy, Grim, or Irwin to unlock Fred Fredburger.
Play as Hoss Delgado:
Successfully complete Mission 9 in Tier 1 in Mission mode to unlock Hoss Delgado.
Play as Mogar:
Successfully complete Story mode with Billy, Mandy, Grim, or Irwin to unlock Mogar.
Play as Nergal:
Successfully complete Story mode with Billy, Mandy, Grim, or Irwin to unlock Nergal.
Play as Nerglings:
Successfully complete Story mode with all characters to unlock Nerglings.
Play as Vikings:
Successfully complete Story mode with all characters and destroy every letter in the credits sequence to unlock Vikings.
