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