Question about Kingdom Hearts toward the end (spoilers)

[Don]

<div style='font: 12pt ; text-align: left; '>I went back and redid the battle at Hollow Bastion, but for some reason Riku seems to be in permanent powered up form. He'd alternate from his ultimate form to his powered up form and obviously there is no way to damage him while he's doing his ultimate attack, and I'm not sure if it's possible to damage him while he's in the powered up form. You can parry his boomerang attack in the powered up form but it actually doens't hurt him anyway which makes me think he's probably invulnerable. He still parries 100% from the front when not attacking and he recovers from his attack way too fast for you to counter in his powered up form. Is there a way to actually beat him if he just never reverts back to normal form?</div>

[the Gray]

<div style='font: 12pt ; text-align: left; '>That's really bizarre Don, I just remember Strike Raiding him to death</div>

[Don]

<div style='font: 12pt ; text-align: left; '>On Normal or on Hard?</div>

[Eric]

<div style='font: 11pt ; text-align: left; '>I don't think anybody else played the game on hard but you and I..</div>

[the Gray]

<div style='font: 12pt ; text-align: left; '>On Expert, I found Strike Raid amazingly useful later in the game in conjuct with Goofy's ability that shares MP</div>