Lost Planet 2

You must earn 1,000,000 career points with the Fight Junkie Faction. The easiest way is to boost this on episode 5, chapter 2 on Extreme (Beat the game on hard to unlock Extreme) as a non-host. Basically, get a friend to host and to invite you. Remember to use the Superstar Ability and to use the Cannon in the second area and you'll earn 60k - 75k each time you do this (Have your friend shoot you with enough T-Energy to get the Cannon to a level 3 shot). Also, I promise you that this level is a push-over even on the hardest difficultty if you are experienced and know what to do.

Achievment name - Fight Junkie Berserker
description - Achieve a career lvl of 99. with the Fight Junkies
To get - earn 1,000,000 career points with fight junkie.

easy way to get this is boost on episode 5 chapter 3 , use the sun gun and have another player charge the canon with TNG energy to push it to lvl 3 which will allow you to take down the boss pretty fast. Just rinse and repeat and you should get this in no time.

Doing the sun gun and activating the post on the other ship with superstar on will get you around 50,000 points a game making only take about 20 times to get to 99.