an opinion...
the song is cool but we need more gackt henshin. although my version of the PV goes like this: tsukasa enters the dark alley only to see that gackt defeats the previous 9 riders (only gackt's punches, kicks and sparks are seen, not his face while defeating the riders one by one, kuuga, agito, ryuki, faiz, blade, hibiki, kabuto, den-o and kiva while tsukasa enters the scene).
tsukasa finally enters the scene, looking at the defeated riders while gackt reveals himself. then the two transforms into their decade forms (tsukasa using his decadriver and gackt using a black decadriver; notice that while transforming, rider images replace the "ghost and symbol effects" with the 9 riders' images for tsukasa and the 9 riders' strongest forms for gackt) and exchange punches, kicks, slashes and blasts.
in the midst of combat, they transform into any of the 9 previous riders. so that means, from tsukasa decade vs. gackt decade, the battle scene goes to kuuga vs. kuuga ultimate, agito vs. agito shining, ryuki vs. ryuki survive, faiz vs. faiz blaster, blade vs. blade king, hibiki vs. hibiki soukou, kabuto vs. kabuto hyper, den-o vs. den-o liner and kiva vs. kiva emperor then back to decade vs. decade, finally sent flying from each other as far as 100 meters due to receiving the slash administered by the other.
in the last battle scene, they execute their dimension kicks (gackt's kick has a scorching flame effect) so strong that the resulting explosion escaped out in the open. as the match draws to an end, the dark place to where the battle took place was filled with smoke, flames burning wild around the place and tons of rubble presumably due to the power of the rider kicks, although the place was not destroyed.
tsukasa recovers quickly from the explosion, standing up only to find out that gackt has recovered too. gackt makes a gesture (like in the PV), but is stopped when the other 9 riders assemble behind tsukasa. our hero looks behind him to see his allies and looks back at gackt, who proceeds to leave the scene while the others' eyes are fixed upon him.
in the end, gackt looks at a kamen ride card showing decade in a different form (not the complete form, but a "spoiler", probably a stronger form) outside, with the entrance of the "alley or warehouse or whatever it is" behind him, with the sun shining above gackt as he looks upon the card.
in addition, they should also add more camera angles and focus on gackt's expression while singing. anyway, that's just an opinion on my part. i like it the way it is. 100/100!