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