That game is a frigging masterpiece. It's not a combatsim, the gameplay is the one of a generic third-person shooter. But the writing...
See, they took the best bits of Apocalypse Now and some pointers from The Heart of Darkness and mixed it up with a bit of interactivity. You don't know what's going on, and what you're really fighting for, but you have to make choices affecting lives, because the voice of an old bastard calls you on the radio.
The choice of setting is brilliant: Dubai ravaged by sandstorms. Luxurious hotels lined with refugee shelters, water and bullets more valuable than abundant jewelry, a civil war in full swing, and this madness got a DJ.
Oh, and the game really mocks modern "realistic" FPS with their ratings Teen and E for everyone - people don't die in clean funny ways here.
There's a demo on Steam, but it's not much in story sense, which is a shame.
The soundtrack is not too shabby either
http://www.2kgames.com/specopstheline/musiccredits/