Spec Ops: The Line (PC) walkthrough:-

0 - Intro Cutscene
1 - The Evacuation
2 - The Dune
3 - Underneath
4 - The Refugees
5 - The Edge
6 - The Pit
7 - The Battle
8 - The Gate
9 - The Road
10 - Riggs
11 - Stealing Water
12 - Alone
13 - The Rooftops
14 - Adams
15 - The Bridge
16 - Ending