Here is the full list of all 66 Alien Swarm achievements.
Awarded for finishing the Jacob campaign on Insane difficulty.
Kill 100,000 Swarm.
Awarded for finishing the Jacob campaign on Brutal difficulty.
Complete any mission on Brutal difficulty with Onslaught and Hardcore Friendly Fire enabled.
Kill 25,000 Swarm.
Kill 100 Swarm with Laser Tripmines.
Kill 100 Swarm with Incendiary Mines.
Complete Timor Station within 4:25 on Normal difficulty or harder without any marines dying.
Complete 10 computer hacks without access being logged.
Kill 250 Swarm with a Grenade Launcher.
Complete Sewer Junction within 1:30 on Normal difficulty or harder without any marines dying.
Complete SynTek Residential within 2:30 on Normal difficulty or harder without any marines dying.
Complete Rydberg Reactor within 3:10 on Normal difficulty or harder without any marines dying.
Complete Deima Surface Bridge within 2:30 on Normal difficulty or harder without any marines dying.
Kill 15 Swarm with all four marines under the effects of a Damage Amp in a single mission.
Complete a campaign on Normal difficulty or harder without any marines dying.
Kill 250 Swarm with a Marksman Rifle.
Kill 250 Swarm with a Rail Rifle.
Deploy 10 ammo stashes that are used by other marines.
Kill 250 Swarm with Twin Pistols.
Kill 250 Swarm with a Vindicator.
Kill 250 Swarm with a Tesla Cannon.
Kill 250 Swarm with a Shotgun.
Complete Cargo Elevator within 2:50 on Normal difficulty or harder without any marines dying.
Kill 250 Swarm with a Chainsaw.
Kill 100 Swarm with Hornet Barrages.
Complete Landing Bay within 1:25 on Normal difficulty or harder without any marines dying.
Destroy all Swarm Eggs in a mission without allowing any to hatch.
Kill 500 Swarm with deployable Sentry Guns.
Kill 250 Swarm with PDWs.
Complete a mission with no friendly fire incidents. Four marines must be present in the mission.
Complete 10 wire hacks without access being logged.
Kill 100 Swarm Grubs.
Kill 250 Swarm with a Flamethrower.
Complete a mission on Normal difficulty or harder without receiving any damage.
Kill 250 Swarm with the Assault Rifle.
Kill 5,000 Swarm.
Kill 250 Swarm with a Prototype Rifle.
Unlock all the available weapons.
Kill 250 Swarm with a Minigun.
Freeze 6 Swarm with a single Freeze Grenade.
Stun 6 Swarm with a single Stun Grenade.
Successfully perform 5 fast reloads in a row.
Heal 300 points of damage in a single mission without dealing any non-melee damage to the Swarm.
Heal all 4 marines with a single Heal Beacon.
Kill 25 drones without friendly fire. Four marines must be present in the mission.
Complete the Jacob's Rest campaign on Normal difficulty or harder.
Complete the Jacob's Rest campaign on Hard difficulty or harder.
Kill a Swarm Parasite with a melee attack.
Kill 20 Swarm with melee attacks in a single mission.
Complete a mission with better than 90% accuracy.
Complete a mission on Normal difficulty or harder without any marines dying.
Roll under a Swarm Ranger projectile.
Successfully perform a fast reload.
Kill 1,000 Swarm.
Seal a door with the welder.
Complete the Jacob's Rest campaign on Easy difficulty or harder.
Kill 6 Swarm with a single Grenade.
Cure an Infested marine.
Kill a Swarm Boomer before it inflates.
Kill 5 Swarm with explosive barrels in a single mission.
Deliver the finishing blow to a Swarm Shieldbug.
Complete 2 co-op missions online. Earns a Team Fortress 2 parasite hat.
Kill 250 Swarm with an Autogun.
Finish a mission without the tech getting killed.
Guard the squad's tech so that he takes no damage during the hack.