How do I beat metroid prime (in the fight)

Well, he is very hard. It took me at least 3 times till I got him. When he turns a diffrent color, match that color with the same beam. For example, if he turns purple, use the wave beam. You must aim for the head first! Also scan him first, that way, you can attomaticly lock on to his head. It would be best if you had most of the rocket upgrades and beam rocket combos. Hope I helped! Good Luck!

The key is to use the right viser at the right time after tha I should be a piece of cake for you. It would also help if you have all the energy cells.

Wat the heck is a phazon fixed cannon

Just beat him myself. You gotta stay out of the way of the missile and beam blasts (missiles, double-jump TOWARD HIM!?! Of all things, beams double jump sideways and immediately counter-attack in either case). Shoot down the energy balls he shoots at you, they almost always drop a power up (energy, missiles, etc.) When he shakes himself, morph ball and roll into the grooves in the floor and go toward him, he'll charge over you. When you come up, lock on and change beams to match his color. Keep repeating this. When he's purple, Wave Buster him when you get fairly close but out of melee range, and when he's grey Ice Spreader his face, it stuns him and then Ice Beam him again. He gets pretty frantic at the end so keep on your toes. Then he cracks out of his exoskeleton, and you have to jump over his wave quakes, and wait until he drops Phazon and he'll go invisible, switch to Thermal or X-ray when he does, stand in the Phazon and blast him until it goes away. If the Metroids he drops harass you, Morph ball and Power Bomb them. Good luck!