Purple Heart: Get wounded or killed in action.
Bronze Star: Get 15 kills
Silver Star: Get 20 kills
Distinguished Service Cross: Get 25 kills
Congressional Medal Of Honor: Get 30 kills
Successfully complete the first twelve missions in campaign mode to
unlock all twelve heroes as playable characters in quick mission and
campaign modes. They include Henry Ramirez, Nigel Tunney, Will Jacobs,
Jack Stone, Guram Osadze, Susan Grey, Klaus Henkel, Buzz Gordon,
Lindy Cohen, Astra Galinksy, Scott Ibrahim, and Dieter Munz.
If you complete the (X) objective for each mission, you will unlock
a new soldier. These soldiers have boosted stats and have their own
specialist weapons. If these soldiers die, you will not be able to
use them except in quick mission mode. You can also use their weapons
in multi-player mode.