Dewy's Adventure

First he will move around and do energy blasts. just move towards the way he does it at you and try not to fall. after awhile he will use his hammer just dodge his hammer blasts. when he hammers in the middle and it's blue turn to water. hit the meteors he shoots. then he will grab dewy and try not to fall in shake ↑↓ really fast. then you see a quick cutscene. turn to ice and press 222 fast near him. after awhile he will chage to his real form. just avoid his attacks and hit him repeatedly eventually he will shoot bad bubbles just get hit by one. then follow the cutscene and beat the game.

Note: you will want a reserve life when you fight him.

Sorry i was doing that answer on the wii(I have the internet channel and typed it on there. I'll refix some parts that were wrong.
First he will move around and do energy blasts, just move towards the way he does it at you and try not to fall. After awhile he will use his hammer just dodge his hammer blasts. when he hammers in the middle, Get to the side and away from the middle and switch to water form. You will be caught in the black hole thingy's wave. Don Hedropn will shoot meteors at you.Hit the meteors he shoots. then he will grab dewy and try to pull you in.Shake Up and down really fast. (If you fail at this part, you will see a cut-scene and then you will take 3 full drops so becarefull)then you see a quick cutscene. turn to ice and press 222 fast near him. after awhile he will chage to his real form. just avoid his attacks and hit him repeatedly eventually he will shoot bad bubbles just get hit by one. then follow the cutscene and beat the game.

Note: you will want a reserve life when you fight him.

www.youtube.com/watch?v=QWCggUKjBvQ
www.youtube.com/watch?v=_1OTv5ZNt_0
(these are not mine! I give credit for them, this may help you a bit.)

Btw, I've completed Don Hedron like 5 times.