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

  Bomber Hunter (15 points): Shoot down 4 bomber planes in 1940. 
  Complete 2001 (30 points): Complete 2001. 
  Formation Buster (10 points): Shoot down all the planes from a single 
  formation 3 times in one game. 
  Missile Attack 1 (10 points): Shoot down 10 bombs in 1910. 
  Missile Attack 2 (15 points): Shoot down 20 homing missiles in 1970. 
  Perfection (20 points): Reach 2001 without losing a life. 
  Reach 1940 (20 points): Complete 1910, making it through to 1940. 
  Reach 1970 (15 points): Complete 1940, making it through to 1970. 
  Reach 1982 (20 points): Complete 1970, making it through to 1982. 
  Reach 2001 (20 points): Complete 1982, making it through to 2001. 
  Rescue Mission (15 points): Rescue 10 parachuters in one game. 
  Smooth Operator (15 points): Reach 1940 without losing a life.