ArmA II: Operation Arrowhead [Single Player Campaign Part 1]
Arma II Operation Arrowhead won IGN's most challenging PC game for 2010.
I was a big fan of the very first Flashpoint, and after the split, ArmA, Arma II And this.
This game is very satisfying if you do it right and its very challenging and fun!
Check it out if you have the chance.
This is part 1 of the series.