So, the only stuff I remember about it is..
Xbox 360 game
Involved White Phosphorus
FPS
At one point you go to a house and it might be your home base and you do some stuff and you come back and everyone is skelified.
When you leave the destroyed house someone says something about being surrounded on all sides.
The beginning of the game had a bus at one point.
There was a level where you fight in a city built into a football stadium?
It was not post-apocalyptic
It is NOT Spec-Ops the line.
Some of it took place in the country.
It took place in america...I think?
At one point you have to fight off a bunch of soldiers and it ends up you kill them with white phosphorus, and that is literally all I know about it.
Good luck with this one guys.