Actually, Tourian changes, because of the whole selfdestruction thing. you can go under what WAS the mother brain, and get a power bomb pack or something.
a super missle pack. Oh, and yes i forgot to mention tourain XD
oh, i dont think im getting zero mission then, i already beat the meat of the game, lol
I’ve tryed this. I can;t beat Arachni-X (Space Jump Guardian)
…that is fusion…but anyway, keep running around the room, and fire when directly underneath
I’ve tried that. DAMN YOU YAKUZA!
Just sit in one of the corners and wait for it to stop go under it and blast it with charge beam or missles and repeat till it’s body falls off and shoot it’s moulth till the X come out and you pretty much know what to do from there. 
the easiest way ive done it combines the metroid2002 guide with the official Fusion Guide. you should stay in morph ball when yakuza is roaming around, and when he opens his mouth, get up and charge your beam, when its full charged, shoot it into his mouth and follow the blast with a bunch of missiles. if you do both, you do maximum dammage. you can do that each time and beat that form really quick. the next one, crouch in a corner, looking up diagonal into the room, and fire missiles CONSTANTLY. you will not only destroy the falling crap, but you will also hit yakuza in the mouth.
The constant firing of missiles is diffecult when you only have 15…