For Astral Chaos - Pathway bonus : Try to beat Alpha Patroklos in Quick Battle mode or reach Player Level 25.
To get Ancient Citadel - Peacetime bonus : you have to clear Episode 4 in Story mode or reach Player Level 7.
Denever Castle - Eye Of Chaos bonus : you must kill Pyrrha Omega in Story mode.

soul calibur v bonus stages
To get Conqueror's Coliseum - Underground Fight bonus : Reach Player Level 13.
For Denever Castle - Assualt bonus : you have to clear Episode 18 in Story mode or reach Player Level 18.
Last Rites On The Battleground bonus : you have to clear Episode 18 in Story mode or reach Player Level 40.
Penitentiary Of Destiny bonus : you must kill Kilik in Arcade or Legendary Souls mode.
To get Tower Of Glory - Spiral Of Good And Evil bonus : you must kill Edge Master in Arcade or Legendary Souls mode.
For Tower Of Glory - Most Holy Dichotomy bonus : you must kill Angol Fear in Arcade or Legendary Souls mode.
For Utopia Of The Blessed bonus : you must kill Elyssia in Story mode.
To get Unknown Forest - Dark Night bonus : you have to clear Episode 7 in Story mode or reach Player Level 21. soul calibur v bonus stages