Download Ace Of Spades
Ace Of Spades is a nice first person shooter game with three levels available for the story mode. They are all linked to each other so you might consider them as linked inside a story. In the game you will encounter not only soldiers but also a masked bandit.
You should not kill the soldiers but you will definitely have to kill the masked bandit as he is your real target and you will need to take him down as soon as possible, but this enemy is pretty tricky to kill and you might have a hard time, especially during the last level.