Accomplish the indicated achievement to get the corresponding number of 
Gamerscore points:

  Star Pupil (5 points): Complete all lessons in the tutorial. 
  First Blood (5 points): Complete the first challenge mission, "Dead Meat". 
  Victor (20 points): Complete all 13 main path challenge missions. 
  Superior Commander (50 points): Complete all 13 main path challenge missions 
  under par time. 
  Future Leader (20 points): Complete all 50 challenge missions. 
  King Of The World (50 points): Complete all 50 challenge missions under par 
  time. 
  Battle Tested (10 points): Complete any 10 challenge missions. 
  Battle Hardened (20 points): Complete any 25 challenge missions.