[Game 1/2/3/4] Clear wave 1. (Each wave lasts 7 rounds of enemy attacks)
[Game 1/3] Clear wave 4 - the final wave of yellow ballistic missiles.
[Game 2/4] Clear wave 4 - the final wave of yellow ballistic missiles.
[Game 1/2/3/4] Clear wave 8 - the final wave of red ballistic missiles and the first wave of cruise missiles.
[Game 1/2/3/4] Clear wave 10 - the final wave of green ballistic missiles.
[Game 1/2/3/4] Reach a score of at least 2000 without ever letting a city get hit.
[Game 5/7] Clear wave 8 - the final wave of red ballistic missiles and the first wave of cruise missiles.
[Game 5/6/7/8] Clear wave 10 - the final wave of green ballistic missiles.
[Game 5/6/7/8] Reach a score of at least 1500 without ever letting a city get hit.
[Game 9/11] Clear wave 10 - the final wave of green ballistic missiles.
[Game 9/10/11/12] Reach a score of at least 1500.
[Game 13/14] Clear wave 13 - the wave that loops forever.
[Game 15/16] Clear wave 13 - the wave that loops forever.
[Game 13/15] Clear wave 13 - the wave that loops forever.
[Game 13/14/15/16] Reach a score of at least 1500.
[Game 1/2/3/4] Clear wave 13 - the wave that loops forever.
[Game 6/8] Clear wave 8 - the final wave of red ballistic missiles and the first wave of cruise missiles.
[Game 5/6/7/8] Clear wave 13 - the wave that loops forever.
[Game 10/12] Clear wave 10 - the final wave of green ballistic missiles.
[Game 9/10] Clear wave 10 - the final wave of green ballistic missiles.
[Game 11/12] Clear wave 10 - the final wave of green ballistic missiles.
[Game 9/10/11/12] Clear wave 13 - the wave that loops forever.
[Game 14/16] Clear wave 13 - the wave that loops forever.