On the start up menu, place your cursor on "New Game" (First option) and input the following buttons: Triangle, Square, X, Triangle Square, X, Circle. Axel/Akutare mode will be unlocked.
Begin game with Axel Mode (US version)
At the start screen, put the cursor over "New Game" and press the triangle, square, and circle buttons twice in that order, then X. You can now play in an Axel Mode that has enemies at reduced levels compaired to if you beat the game and went to Axel Mode. Axel Mode offers several new gameplay features exclusive to the PSP port that carry over to the normal mode when beaten.
Characters
Complete the indicated task to unlock the character.
Character
How to unlock
Asagi (Humanoid)
Raise Asagi's level to 2000 and pass her bill as a senator.
Asagi
Unlock her map with 33 Felonies, 100 mana, and at any time after the first playthrough, defeat her and pass her bill as a Senator.
Celestial Host
Clear Akutare mode 3-3 and they will be available to create.
Disgaea Ronin
Have a Disgaea 1 save file. (Regions must match)
Entei Monster Class
Beat Akutare Mode 2-3 and they will be available to create.
Flonne
Unlock ES8 with 40 hours game time and during Episodes 12-13. Defeat her and she'll join.
Gordon
Unlock Extra Stage 4, and pass his bill after completing it.
Laharl
After obtaining Flonne, pass Flonne's bill as a Senator and beat ES9.
Mao
Unlock his stage after obtaining Champloo and Raspberyl.
Marjoly
Unlock ES7 with 99 Felones, 1500 mana and at any time and defeat her. After, pass her bill.
Mass Produced Kurtis
Beat Extra Stage 4 and you will be able to create them.
Mr Champloo
Unlock his stage with 50 hours game time and Akutare mode clear.
Preire
Unlock ES6 with 66 Felonies, 100 mana and during Episode 1-9 and defeat her. After, pass her bill.
Raspberyl
Unlock her stage after clearing 30 Dark Sun Stages and obtaining Champloo.
Sabre Kitties
Unlocked after clearing Akutare Mode 1-2.
Vyers/Midboss
Unlock ES5 with 20 hours of Game time, 400 mana and in Episode 1-9 and beat his stage. On the next playthrough, get the stage again and pass his bill.
Zetta
Unlock ES11 with 10 Dark Sun Maps cleared and 3000 mana. Clear the map and pass his bill afterwards.
Completing the level 3 in the Caves of Ordeal
This level features level 150 monsters, an aura that decreases your stats by at least half, Geo Panels that forbid you to throw, and warps. They will usually cast Super Egg, which will hurt your characters if they are grouped together or alone, dealing strong damage. To deal with this problem, create a White Dragon class monster. Their aura effect is immunity to non-Special (Element) Attribute Attacks. Because Super Egg is a physical Attribute Attack, the White Dragon class monster should be immune to the attack, thus losing no HP unless they physically attack you. Make at least three to five White Dragons, leveling them up to about level 100 to 125 to complete this level. Otherwise, level up Adell and his gang to at least level 120, dealing them the hard way. It is also recommended that you have at least two to three high level Beast Tamer human class to help the White Dragon class monster in Attack, Defense, Magic, and EXP. After killing all the "white chicken" monsters, bring out your main characters. Do not destroy the Warp Geo Panel, located near the No Throw Geo Panel, which is found on the sides of the "red chicken" monster. Let it warp you to the near top end where the "red chicken" monster is located. Move your characters in the panels that have no Geo Panel, then either throw a White Dragon or your main characters up there and finish the stage.
Endings
Complete the indicated task to unlock the ending.
Ending
Task
Axel (Akutare in JP) Ending
Get Defeated by Axel/Akutare.
Bad Ending
Have Adell 10+ felonies, Killed Ally 50+ Times, Then Finish The Game.
Etna Ending
Defeat Etna in Chapter 3.
Laharl Ending
Defeat Laharl in Chapter 11.
Middle Boss Ending
Defeat Mid-Boss Before Chapter 4.
Tink Ending
Defeat Final Boss with Lvl. 1000 Tink.
Worst Ending
Have Adell 99+ felonies, Killed Ally 99+ Times, and Rozalin (Rossary in JP) ally-killed by Adell.
Extra Classes
Note that just having the mastery isn't enough you'll then have to petition the Dark Assembly with the appropriate bill to be able to create them.
Class
How to unlock
Archer
Have someone with a level 5 bow mastery.
Beast Tamer
Successfully capture a monster.
Chaos Soldier
Finish the game once.
Druid
Perform a 500+ Geo Combo.
Female Ninja
Have someone with a level 5 fist and staff mastery.
Gunner
Have someone with a level 5 gun mastery.
Heavy Knight
Have someone with a level 3 spear mastery.
Magic Knight
Have someone with a level 3 sword and staff mastery.
Male Ninja
Have someone with a level 5 fist and sword mastery.
Samurai
Have someone with a level 5 sword mastery.
Sinner
Someone in your party becomes a criminal.
Land of Carnage
To unlock the Land of Carnage (a mirror world of every level with super difficult enemies), collect all 16 treasure maps from the different pirates in the Item World.
Magichange
Successfully complete Axel mode and start a new game session in Adell mode.
The Lord Of The Rings reference
The Elven Bow's description states that it was used by an elf in a quest to destroy a ring. The elf mentioned was Legolas, and the ring mentioned was the One Ring.
Throw characters through No Entry panels or tall terrain
As long as the obstacle is only one square thick, you can throw through it. Stand next to it and lift a character, then extend your throw through the obstacle. Retract your throw range (toward the thrower) and press X at the same time. There is a "sweet spot" to do it right, but because there is no penalty to missing it (you just get an error sound) you can keep extending and retracting while mashing X until you throw straight through the obstacle.
Unlimited Magichange turns
Throw a character back in the base panel and to get unlimited turns for Magichange.
