I beat it yesterday and thought it was tre easy. It seems like every game i play the last boss is the easiest!!
Lord the hardest boss in the kingdom hearts games will ALWAYS be the same person:
Sephiroth. GOD i hate that man with his long sword and his hair and his poofing abilities and his hair and his wing and his hair!

RAWR! And then i didnt get to beat him before i ended the game because i went into that door at the end thinking i could come out again...well obviously yeh cant and i thought the last boss would kill me but he didnt and i beat the game. That happened with the first kingdom hearts too. i always win on accident. oh well

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WARNING! DO NOT READ THE FOLLOWING UNLESS YOU DON'T CARE ABOUT KNOWING THE ENDING BEFORE YOU COMPLETE THE GAME BECAUSE I DO NOT KNOW HOW TO DO THE SPOILER BOXES
I also thought the ending was kinda sad. but i always think endings are sad because the thing is over and now im TRE anxious for kingdom hearts tres(3)! Okay so a 3rd one isnt confirmed but i always know when there's gunna be another of something. And plus...seeing the end of Kingdom Hearts 2 with the note from the king and the secret ending with the metal armor people who are in what looks like a graveyard type place of keyblades (which COULD imply #3 is about past keybladers possibly)...i think its kind of a give-in that there be a 3rd.
And i also thought it was sad that Axel poofed away and Roxas and Naminé shimmered into Kairi and Sora and couldn't stay outside and get untransparent and get hearts because i did like all those people.