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