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