This should take you like 8 minutes. This guide is long because of weapon must haves and stuff. To have enough ammo, you should go throught the game using only the bomb glove, pyrociter, blaster, glove of doom, devastator, suck cannon, morph-O-ray and visibomb gun. the cash not spent on the other stuff will save up. When you fight him use giant clank and face him and press triangle, which will shoot a energy bomb, then pound on him with your fists of steel, when the first segment of his health bar is just at the end, shoot another energy ball with triangle. this will go into the next segment of his health and save ammo and health when fighting him. then he will shrink clank. piggyback time on clank is over. Refill your ammo if need be at the vendor. then put the following weapons in your quick-select, pyrocitor, suck cannon( gold version will make it a lot easier), devestator, gadgetron PDA, swingshot, blaster, and bomb glove. Then equip the thruster pack. you CAN NOT use the heli pack when fighting him. You can eqip the 8th weapon slot with anything else EXCEPT the visibomb gun. and you have to have at least the primium nanotech( the ultra version would be a lot more helpfull). Rip him a new one with your devastator untill his segment is empty. Drek will now fire a laser at trhe ground which will crumble so make sure you are not on a part that falls.you are probably pretty low on devastator ammo right now so that is where your PDA comes in handy. note the price doubles on the PDA because of "shipping and handling" so it should cost about 2 grand to refill 20 shots. now swing shot after him. he damaged a platform on his escape so watch out for that. also the platforms will fall when you land on them so you only have a second or two to jump off. when you land on the next area he should spin around and shoot mines at you. use the suck cannon to suck up all the mines is can hold then avoid the mines untill he fires a big ball from his robots arm. jump over the red rings it makes when it blows up then fire the mines at him. it will chip away at his health a little. then fire your devastator untill he launches more mines. repeat the process untill he fires his big laser and scoots his tin can butt out of there. Use the PDA and fill er up. then chase after him. this time he monolouges in a cutscene about how brilliant his plan it to make cash. then he presses a button. you have 28 seconds to make it to the center of the area and power slam your rocket powered butt onto the button. dont take too long tho beause he will press it 2 times again later in the amount of time you had left. then he will put a red ring around the bottom of his bot and try to run into you. run towards the edge, jump onto the rim and ride the grind rail to escape him. this time he will fire out mines and evil agents of doom, so dont think you accedentally tossed some out. suck up whatever he throws at you then when the suck meter is full take out the pyrociter and toast any doom agents that are running around. then fire the mines at him. he will not toss out the bombs like before. that now is a random attack, he will do it whenever he chooses. suck up anything around you and shoot at him untill he starts firing out green missiles. theese are not good. dodge em and kill him. then after a secont you have to fire the planet disentigration laser at his new planet he made. butt slam the button to make the planet go boom!!! ta-daaaaaaaaa!! you have beat him.