Successfully complete all Arena missions, then use the following combinations with the "Customize Armor" option:

Fleet: Helm of Swiftness, Leather Jerkin, Bone Shaffron, Leather Drape, Leather Crupper
Guardian: Chain Coif, Cuirass of Heroes, Chain Shaffron, Faceted Peytral, Chain Crupper

Successfully complete Arcade mode to unlock Boss Attack mode.

Successfully complete the indicated task to earn the corresponding medal:

Air Burner: Destroy more than six enemy air units with an AA gun or AA missile launcher.
Air Frightener: Destroy all enemy air units in a certain number of cycles.
Air Keeper: Have no air units lost.
Bohemian Pacifier: Destroy more than ten enemy units with light or heavy artillery.
Bombing Master: Destroy more than three enemy units with bombers.
Demon Of The Sea: Destroy more than three enemy units with submarines.
Exceptional Marksman: Destroy more than six enemy units with long-range units.

At the title screen, press L, R, Left, Right, Square, Circle, X, Triangle to unlock Situation 8.

Find a location that contains life recharge power-up above a lava bed. Intentionally lose almost all your life. Jump into the lava and simultaneously use the life power-up to resume game play at the next level.

Locate the area on level 1 with the stars that mark completion of the level. Use the helicopter or spring pads to enter a hidden room in the ceiling to collect all the weapons and remotes.

First, enter "KOEJEMJOKBPNMOFJ" as a code to unlock the ability to enter "Content Codes" from Dungeon Siege 2: Broken World on the PC. To get "Content Codes" for use in Dungeon Siege 2: Broken World, purchase items with crossover tablets from Klars in Seahaven. You can then choose the "I need a code for use in Broken World" option. "Content Codes" for Dungeon Siege 2: Broken World will now appear under the "Master Code". Enter them in Dungeon Siege 2: Broken World to unlock items.

At the title screen, highlight the "New Game" option, then press Triangle, Square, Circle, Triangle Square, Circle, X. If you entered the code correctly, you will hear Etna's voice. In the Japanese version, highlight the "New Game" option at the title screen, then press Triangle, Square, X, Triangle Square, X, Circle. Alternately, successfully complete the game after reading Etna's entries in her secret chamber. To enter Etna's secret chamber, press the two secret buttons in Laharl's Castle. The first button is behind the throne. The second button is inside the skull on the counter in RosenQueen's store. After both buttons are pressed, go to the room where Longinus, Ghoss, Stigma, and Gargo are usually found. Press X in the corner behind Stigma to reveal the door.

Get an "A" or better rank on all twelve acts to unlock Secret Act 1.

Successfully complete Si Shui Gate (Dong Zhoug's side) 100% in Free mode to unlock Diao Chen.

At the main menu, select the "Extras" option. Then, choose the "Cheats" selection and enter one of the following codes to get the corrsponding number of reward points:

100 points: BULLETPROOF
100 points: CROOKLYN
100 points: DASTREETS
100 points: DUCKETS
100 points: GETSTUFF
100 points: GOUNDRGRND
100 points: NEWJACK
100 points: REALSTUFF
100 points: THEEMCEE
100 points: THESOURCE
200 points: DRAGONHOUSE
200 points: REAL STYLE
200 points: SUPER FREAK
300 points: NEWYORKCIT