Here's my personal takedown method for grinding Dark Phantom kills. I'm doing this on Version 1.1 since I like not paying money for jewels and making the 5G grindfest also count toward the awakened skills achievement.
Main Skill: Plasma Ray
Sub Skill: Anima Bullet ++ (every kill grants bonus Willpower)
Action Skill: Lunatix ++ (increases attack for 2 Willpower and 2HP)
(Lunatix++ is supposed to only cost 1 Willpower and some HP, but on 1.1 at least it takes 2 Willpower instead, but the boost is still greater than Angriff Adler ++.)
Select Story Mode, World 5. As soon as the cutscene begins hit the Fast Forward button. I pick World 5 because on 1.1 I'm still getting fifteen jewels a pop. Also on Air of Despair you only begin with one health.
Once the stage starts and you see Dark Phantom's health bar fill, switch on Anima Bullet ++ and kill some of the Vespins that swarm you. You don't need to hit that many, just enough to get your Willpower up to 2.
Once the Dark Phantom shows up and does his thing, activate Lunatix ++ the moment he becomes vulnerable and give him the good ol' Plasma Ray spam.
When you've learned his flight path and got it down pat you will be able to do some ridiculous damage to him in this phase.
Don't worry so much about getting hit, just concentrate on Dark Phantom because he'll go down before you do. If you're flawless you can actually take him down during this phase but you probably won't.
For his next phase where he fires his large beams I like to fly from the extreme bottom to the extreme top and vice versa, meaning my lasers can still hit him rather than be absorbed by the beam.
He'll either do two beams before his ball and shield attack and final attack, or you might get lucky and he'll do three beams before being forced right into the final attack. Whatever happens, just keep tapping that screen!
Once the battle's over mash your way through the results screens, then once the cutscene begins hit the BACK button on your phone. This will return you to the skills menu, skipping the cutscene and credits entirely!
And there you have it, the fastest I have ever defeated him this way is with 244 remaining on the clock if I beat him during his first phase, but I usually get 237-241. If anyone's got a faster method I would love to hear it.
EDIT: Even in its glitched state Lunatix ++ is still the better skill.
Last edited by Exu; 01-18-2013 at 07:54 PM.