^ Actually, it's funny you mention the problem with the Arial Slam because that's one of the biggest things that kept killing me. I would often get blindsided because I registered that third/fourth hit meaning that he'd always hit me from behind which would either kill me or leave me needing to heal whereupon he'd kill me afterwards.
In regards to the Thunder Surges, I should have been a bit more specific. I only need to spam it whenever Vanitas' Lingering Sentiment has entered into his Shotlock. The rest of the time, I'm just hitting, blocking and dodging like a madman.
Anyway...
Ladies and Gentlemen, STATUS REPORT:
Player Character: Terra
Difficulty Level: Critical Mode
Current Level: 45
Location: Mirage Arena
Current Commands: Thunder Surge, Potion x5 (used for 6 slots)
Welp, it took me many hours (at least three nights worth) and many chances for me to experience premature baldness, but I FINALLY DID IT! I BEAT VANITAS' LINGERING SENTIMENT/WILL/SPIRIT/THINGAMAJIG LAST NIGHT!!!
Holy crap, did this take me forever, but once I finally figured out what it was that I really needed to do, it only took me an hour to really get it right. My biggest mistake initially was thinking that the Arial Slams would be able to save me from above. This was technically true...until it ran out and I was left in the air for about a whole second which is more than enough for him to get attacked and/or killed. So from there, I equipped Thunder Surges instead. However, I was still losing, so upon a little further research, I realized that I would be better off forsaking my one revenge technique (Payback Fang, I think it was called) and replaced it with Arial Recovery instead. This ensured that I didn't die accidentally using the Payback attack and getting hit by the X-shaped attack instead (which usually killed me).
So here's the lowdown. I used Chaos Ripper for my Keyblade. I would then start the battle by dashing and immediately attacking him. From there, I either dodge his attacks or go into Shotlock and use Sonic Shadow to completely forgo the
Kagebushin no Jutsu attacks one attack where he summons makeshift copies of himself to attack me. Whenever there was an instance where I felt he would just strike (relatively) normally and/or when he decided to spam that attack and disappear only to attack thing again, I just block and use Counter Hammer for great damage. From there, if I had filled up the gauge, I would use a well timed finisher (in this case, Explosion). Finally, when he enters into his Shotlock, THAT is when I finally spam the Thunder Surges. In fact, it was a Thunder Surge during his use of that one Shotlock that ensured my victory.
Speaking of which, lo and behold:
So yeah, one Super Boss down!
I might take down another couple of Matches before even attempting to defeat the Mysterious Figure/
Trollenort Young Master Xehanort. I'm also probably going to get Rhythm Mixer while I'm at it, too.
EDIT: OK, pictures are in. If they're not there still, I may need to resize them.