When you meet the indicated requirements you will get the corresponding ending.
Unlock Normal Ending:
Don't meet any other ending's requirement.
Unlock Human World Ending:
Before you reach stage 7-6 kill more then 99 allies and clear 2 alternate stages.
Unlock Raspberyl's Ending 1:
Lose against Raspberyl on stage 1-5
Unlock Raspberyl's Ending 2:
Lose against Raspberyl on stage 2-1
Unlock Almaz's Ending:
With only Almaz win stage 8-4 and the ensuing battle.
Unlock Laharl's Ending:
Go to Homeroom and propose 'Watch a New Ending' and clear the stage.
Unlock Mao's Ambition Ending:
Before reaching stage 4-4 clear stage 1-9 on 2nd or higher cycle.
Unlock Super Hero Ending:
To defeat the final boss use Mao at Level 500 or higher.
Added by: Sanzano Apr 23rd 2012, ID#24