Unlockable: Activate Cheat Menu
Input L, R, L, R, BLUE, WHITE, BLACK, BLUE on the main menu.
Unlockable: Extreme Difficulty
Finish the game on Normal or Hard Difficulty.
Hint - Final Misson
You only need one soldier to complete the last misson of the game. Since you lose the mission if time runs out, you need to ruthlessly expend your squad so just one guy can reach the objective.
