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