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