Here is the full list of all 35 Insurgency: Sandstorm achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Call in fire support ten times as an Observer.
Destroy an enemy air support vehicle.
As a Commander, kill an enemy using fire support.
Win a match of Checkpoint.
Capture 100 objectives.
Win a match of Firefight.
Win a match of Push.
Capture an objective as the last member of the team alive.
Destroy an enemy weapon cache using a remote explosive charge.
Successfully rig and destroy an enemy weapon cache.
Be the Most Valuable Player of a round.
Kill three or more enemies with a single grenade or explosive.
Destroy an enemy vehicle with a mine.
Kill an enemy after blinding them with a flashbang
Kill an enemy while blinded by a flashbang
Kill 3 enemies with a headshot in a row.
Kill an enemy with the last bullet of your magazine.
Kill an enemy by burning them.
Kill an enemy while vaulting.
Kill an enemy with an enemy's live grenade.
Kill an enemy with a vehicle.
Kill an enemy driver with the mounted weapon of their vehicle.
Drive a vehicle full of teammates for more than 15 seconds.
Kill an enemy by bashing in a door.
Get the first kill in a round.
Navigate through chemical gas while wearing a gas mask.
Purchase your first item in the Appearance menu.
Kill an enemy with a knife.
Kill an enemy right after performing a speed reload.
Kill an enemy without using weapon sights.
Kill an enemy using the mounted weapon on a vehicle.
Complete the tutorial mission.
Kill an enemy by shooting through something.
Kill an enemy while they are reloading.
Block an objective from being captured and then clear it.