Although the setup sounds like it, Spec Ops: The Line is not your ordinary modern military shooter. The single player campaign is pretty short. It comes to tell a story, makes its point, and finishes, without any obviously unneeded parts or sidetracks. So this post will be likewise.
The story is about horrors of war. It has some stressful and regrettable choices. The setting is outlandish, I think: Dubai during a months long sandstorm that blocks everything. (It's on the coast; couldn't they use boats to evacuate?) I'm not sure if there are any right choices, because it seems that your squad will fight regardless. The ending takes a very psychological bend. Even thinking a bit about it, I'm not sure what was real and what was a hallucination.
The gameplay and graphics are what one would expect of a 2010s-era cover-based shooter built on Unreal Engine 3. They're OK. The controls were a bit whacked, as I kept switching weapons instead of reloading them. I could never remember the grenade hotkeys in a firefight, so I never used them, unlike the reload prompt, which seems to appear when your clip is mostly full.
Overall, this is a quick game. I'm not sure if it's worth the $30 asking price though, even with the free (unplayed) coop mode.