Disgaea 2: Dark Hero Days Cheats :
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.