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