Special Edition of the Game

Major Changes from the Original Game

New Playable Character Vergil

Vergil has a new play-style and weapons compared to Dante. However his campaign pretty much follows Dante's 1 to 1, with different cutscenes at the beginning and ending of the game.

Bloody Palace

Fight waves of enemies up until you can reach level 9999. You cannot save or use items in Bloody Palace.

Pillars

Fire Pillar:

Lets you jump up 100 levels.

Water Pillar 

Replenishes your health but only lets you jump up 1 level.

Lightning Pillar

Replenishes your Devil Trigger and lets you jump up 10 levels.

Very Hard Difficulty Level Added

Identical to the Hard Mode in the US original, which was made much harder than Hard more in Europe and Japan. Meaning that there are 5 difficulty levels to choose from.

Special Edition's Hard Mode

The special edition's hard mode is as difficult as the hard mode in the European/Japanese standard release.

Difficulty Levels Adjusted

Gold Orb Continue System

Gold System

Allows the player to have unlimited continues, where users can hold up to 3 Golden Orbs to revive themselves in battle.

Yellow System

Allows the player to have up to 99 Yellow Orbs to revive themselves while playing the game.

Demo Digest

Allows the player to view different cutscenes from the game.

Turbo Mode

Increases the game's speed by 20%.

Note on PAL DMC3:SE

PAL region Special Edition does not support turbo mode and just has normal speed instead.

Optional Boss: Jester

First Encounter is required for Jester. The second and third ones can be skipped.

New Costumes

Dante Costumes

Dante's former Super Dante unlocked by completing Very Hard:

• Has unlimited Devil Trigger
• No longer replenishes health
• Devil Trigger is drained after doing a DTE
• Devil Trigger is drained after using Quicksilver
• Devil Trigger is drained after using Doppelganger

Super Sparta unlocked by completing Dante Must Die:

• Health is replenished
• Devil Trigger is never drained

Vergil Costumes

Coat-less Vergil

• Same abilities as standard Vergil

Corrupt Vergil

• Turns into Nelo Angelo during Devil Trigger

Super Vergil

• Same as Dante's Super Dante Costume

Super Corrupt Vergil

• Same abilities as Corrupt Vergil
• Pretty much a tank/God Mode

Buffed Dullahans

• Will charge at you if you get too close.
• Home in quite accurately
• Tough to evade without getting chip damage
• Replace other enemies in some missions like the Blood-goyles in Mission 14 in Easy/Hard Mode

Alteration to Jump Cancelling Mechanics

More cancelable frames introduced, you can get more aerial attacks in before the enemy drops to the ground.

Source:

Grabbed from User: JochNessMonster from GameFAQs