Successfully - Devil May Cry
Successfully complete missions 1, 2, or 3 while using at least one continue. At the start of the next mission, there will be an option to change the game to easy mode. Note: Once easy mode is activated you cannot return to normal mode.
Successfully complete the game once to unlock Hard mode.
Legendary Dark Night mode
Successfully complete Hard mode to unlock Legendary Dark Night mode.
Dante Must Die mode
Successfully complete Legendary Dark Night mode to unlock Dante Must Die mode.
Super Dante mode
Successfully complete Dante Must Die mode to unlock Super Dante mode. In this mode, you can transform into a devil, and use magic indefinitely.
All-star group photo
Successfully complete the game with an "S" rank on all missions to unlock the all-star group photo.