i beleive taht his keyblade only snaped because it was frozen which makes anything able to break easier, i think his blizzaga was actually liquid nitrogen, making everything as soft as glass, but his body never broke, which is confusing.
Well, if you want to be REAL about it, having part of someone's body shatter is alittle gruesome. And greusome + Kingdom Hearts don't mesh. You don't see blood ONCE in the game.. so yeah.
If you want to be technical, Aqua caught him.
And just to interject my personal theory..
I think all the keyblades in that place in the secret vid are the predescors(sp?) to all the keyblades now. For example, you see the Fenrir keyblade at one point. Well, that could be the Fenrir before it got made into a keychain, etc.
Because the Keyblades were so powerful, and there were literally thousands of them, they had to devise a way to limit their power. So they only made a few keyblades, and turned all the other keyblades into keychains so you could still summon the power of the other keyblades without just anyone being able to wield it.
For example, the old guy has Terra's keyblade in his hand at one point, etc.