you have to remember all the enemy positioning and switch forms accordingly.
level starts you off in a canyon w/ shit loads of small, easy to kill flying creaters. glide wing blast them away, after a while it's easier to keep to the back view as the pods appear. switch to regular form, lock onto pods, blast them away. remember their locations and switch view before you arrive. left, top, right, around 8/9 pods every time.
take care of any stray fire by using your pistol.
then you arrive upon the division, follow the worm, the valley is tougher. swing down/up to avoid collision. keep to glide wing, take care of those buttefly thingies.
then the fast speed swoop through the tunnels. remember number of enemies and postioning, aim before you arrive and fire in their general direction w/ glide wing. lots of bonuses.
during the worm boss encounter, stay on regular form and keep blasting them away, use regular pistol shot to take care of any stray fire.
they'll rise up...recognize this move, as they rise up...use the speed boost to burst away, and they'll miss. rinse and repeat. easy. use special techniques when possible.
behind the falls, take care of the swarms with glide wing first. then you encounter the rays. if you arent good enough, dont try to kill them, just protect yourself from their fire and get through the area.
the boss is just easy. boost to his back, keep hitting him till he flies off. keep hitting him. whenever he moves such that he is facing you, just postion yourself behind him. and keep hitting him. there are times he'll have a bunch of butterfly thingies circling him and they'll fly off and hit you...basically as they are circling him, kill them. rinse repeat, use special. done.
w/ a shooter like this, dont just play it, this is an artform. use your brain. memorize.