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