Heres how to defeat each boss:
Frostwind: First, when it comes out of a hole, shoot it. Then youll be in a chase. beware. even with the invincible cheat on, you can still die from it. Now, once you get to the end, youll see heather in a SD (shadow goo) cage. now frostwind will glide over the stage. dodge her icicles. then itll come up abit. shoot it, and shell crash down. ground bounce her. repeat 4 times.
Deadwood: First find the acorns and shoot them down. he'll shake when an acorns destroyed, aswell as about every 7 secs. then youll enter its mouth when hes ded. youll see Samuel in an SD cage, then youll have to vs a wierd shadow goo guy. if youve played metroid prime 3 on wii, youll reconize these other things. DONT touch them. shoot the guy 4 times, but hes fast.
Angler King:God, I hate the chases! after it, he'll shoot out 3 shadow fish. kill em, and hell charge. notice the bubbles. shoot him continuasly, or let the starzooka do play follow the leader. eventually hell shoot 3 more S fish. and eventually youll kill him!
Scorpion+Wilfre: for the scorp, use your sword and protect urself. then hell shoot some...gas! dodge it, and the second time, your platforms will appear. at the second platform, ground bounce him. for wilfre, hell shoot your trident. only swipe him wen he crosses sides.