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