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