Birth by Sleep experiment 221 help?

right now birth by sleep is my kingdom hearts addiction. on my terra file, im stuck on the fight with experiment 221. he seems overpowered. can anyone tell me how to beat him?

 

If you can't figure out a method, you can always take the failsafe route that applies to all storyline bosses: Level grind. You'd be surprised how much a couple of levels changes the difficulty.

 

Use your shotlock whenever you think you may take to much damage (your invincible during shotlock.) Also use Fire commands. They follow him and do a very small amount of damage, but when you enter the Firestorm command style, all your normal attacks knock him back. When he is inside the guns, don't damage them, just focus on blocking. I suggest you use the "Mark of a Hero" keyblade.

 

I suggest you run around and figure out his attack patterns. Wait for an opening when the thing is vunerable - you also should level up a couple of times if you're still having trouble.

 

Block-counter...it works a lot of the time, damages him and knocks him back. Like everyone else says, watch all his moves and eventually you learn his patterns and can defeat him.