Omega Pirate
Okay, when you enter the room, Scan the Omega Pirate before you approach him and he gets out. He has 4 areas of Phazon Armor that protect him (each shoulder and each leg), lock on to one (L), charge up the Power Beam (hold A), hold it and wait until his hand isn't glowing to let off a Super Missile (Y) while jumping (B+B) over his wave attacks. Once all 4 are gone, he'll kneel and call some Pirates; you can fight them if you want, but if you keep moving around they shouldn't hurt you too much. Eventually Omega will appear in one of the Phazon patches to restore his armor - you'll need to put on your X-Ray Visor for this. Lock on to him and fire another Super Missile to actually damage him - you can hit him twice if you're fast enough; he'll then disappear and reappear in another Phazon pool - nail him again with a Super Missile if you have time. When he reappears, go back to the Combat Visor and repeat the process (attacking the 4 areas of Phazon Armor) - his wave attacks should take out the rest of the Pirates for you, just keep moving and make sure you pick up any Ammo or Health that they leave behind. It takes about 4-6 Super Missiles when he's recharging to finish him. I suggest finding as many Energy Tanks and Missile Expansions as you can before you face him. Once you beat him, you get the awesome-looking Phazon Suit, I like it anyway; good luck, hope that helps =)
More tricks, tips and cheats for this game are right here - Metroid Prime cheats
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