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