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