Vergil story mode
Have a saved game file from Devil May Cry 3: Dante's Awakening on your memory card. Alternately, successfully complete the game under any difficulty setting.
Easy difficulty
Intentionally fail a mission under the normal difficulty setting three to five times. A message will appear, stating that you have unlocked the easy difficulty level.
Alternately, successfully complete the game under the normal difficulty setting.
Hard difficulty
Successfully complete the game under the normal difficulty setting.
Very hard difficulty
Successfully complete the game under the hard difficulty setting.
Bloody Palace mode
Have a saved game file from Devil May Cry 3: Dante's Awakening on your memory card. Alternately, successfully complete the game under any difficulty setting.
Dante Must Die Mode
Successfully complete the game as Dante or Vergil under the hard difficulty setting.
Super Dante
Successfully complete the game under the Dante Must Die difficulty setting to unlock Super Dante as a character. He has an unlimited Devil Trigger.
Super Vergil
Successfully complete Bloody Palace mode to unlock Super Vergil as a character. He has an unlimited Devil Trigger.
Coatless Vergil
Complete Vergil story mode under the easy difficulty setting.
Sparda Costume (Vergil)
Successfully complete the game as Vergil under the hard difficulty setting to unlock a costume to make him appear as Sparda from the original Devil May Cry.
Alternate ending sequence
Defeat at least 100 opponents as Dante during the ending credits.
Gallery items
Complete the game on Easy or higher to unlock Gallery mode. Complete the indicated task to unlock the corresponding item in the Gallery.
Bonus Art 1: Complete the game under the easy difficulty.
Bonus Art 10: Get an "S" rank on all missions in Dante Must Die.
Bonus Art 11: Get an "SS" rank on all missions in Easy.
Bonus Art 12: Get an "SS" rank on all missions in Normal.
Bonus Art 13: Get an "SS" rank on all missions in Hard.
Bonus Art 14: Get an "SS" rank on all missions in Very Hard.
Bonus Art 15: Get an "SS" rank on all missions in Dante Must Die.
Bonus Art 2: Complete the game on Normal.
Bonus Art 3: Complete the game on Hard.
Bonus Art 4: Complete the game on Very Hard.
Bonus Art 5: Complete the game on Dante Must Die.
Bonus Art 6: Obtain an "S" rank on all missions in Easy.
Bonus Art 7: Obtain an "S" rank on all missions in Normal.
Bonus Art 8: Obtain an "S" rank on all missions in Hard.
Bonus Art 9: Obtain an "S" rank on all missions in Very Hard.
Concept Art, E3 Promotional Video, Crazy Gameplay Video: Complete the game on Easy or Normal.
Event Promotional Video, Devil May Cry 3 Original Demo: Complete the game on Very Hard.
Hi-Res CG Art, Kazuma Kaneko's Illustrations, Motion Capture Video, Video Storyboard: Complete the game on Hard.
Mundus reference
Complete the game and get the Vergil ending, where he falls down in the pool of blood. There will be three round and red electric orbs that he says he could defeat if his father did it. This is most likely Mundus, the last Boss from the first game, because Vergil obviously loses and succumbs to Mundus' power.
Glitch: Shadow
In any mission when playing with Dante's last costume (Super Sparda), look at his shadow on the ground without Devil Trigger on. It should resemble Dante's DT form even though it is a different character.