Here is the full list of all 66 Alien Swarm achievements.
Kill 100,000 Swarm.
Kill 25,000 Swarm.
Complete Landing Bay within 1:25 on Normal difficulty or harder without any marines dying.
Complete a campaign 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.
Complete Cargo Elevator within 2:50 on Normal difficulty or harder without any marines dying.
Awarded for finishing the Jacob campaign on Brutal difficulty.
Awarded for finishing the Jacob campaign on Insane difficulty.
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.
Complete Sewer Junction within 1:30 on Normal difficulty or harder without any marines dying.
Complete any mission on Brutal difficulty with Onslaught and Hardcore Friendly Fire enabled.
Complete 10 computer hacks without access being logged.
Complete Rydberg Reactor within 3:10 on Normal difficulty or harder without any marines dying.
Complete the Jacob's Rest campaign on Hard difficulty or harder.
Kill 250 Swarm with a Grenade Launcher.
Kill 6 Swarm with a single Grenade.
Kill 250 Swarm with a Marksman Rifle.
Kill 100 Swarm with Incendiary Mines.
Kill 250 Swarm with a Chainsaw.
Complete 10 wire hacks without access being logged.
Kill 250 Swarm with a Vindicator.
Kill 15 Swarm with all four marines under the effects of a Damage Amp in a single mission.
Complete a mission on Normal difficulty or harder without receiving any damage.
Kill 250 Swarm with a Rail Rifle.
Deploy 10 ammo stashes that are used by other marines.
Kill 250 Swarm with Twin Pistols.
Kill 250 Swarm with a Shotgun.
Kill 100 Swarm with Hornet Barrages.
Kill 250 Swarm with PDWs.
Kill 250 Swarm with a Prototype Rifle.
Stun 6 Swarm with a single Stun Grenade.
Kill 100 Swarm with Laser Tripmines.
Heal 300 points of damage in a single mission without dealing any non-melee damage to the Swarm.
Kill 5,000 Swarm.
Kill 250 Swarm with a Flamethrower.
Freeze 6 Swarm with a single Freeze Grenade.
Kill 250 Swarm with a Tesla Cannon.
Kill 250 Swarm with the Assault Rifle.
Seal a door with the welder.
Kill 20 Swarm with melee attacks 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.
Unlock all the available weapons.
Kill 100 Swarm Grubs.
Kill 500 Swarm with deployable Sentry Guns.
Kill 250 Swarm with a Minigun.
Cure an Infested marine.
Deliver the finishing blow to a Swarm Shieldbug.
Destroy all Swarm Eggs in a mission without allowing any to hatch.
Kill 1,000 Swarm.
Kill a Swarm Parasite with a melee attack.
Kill 5 Swarm with explosive barrels in a single mission.
Kill 250 Swarm with an Autogun.
Complete a mission with no friendly fire incidents. Four marines must be present in the mission.
Complete a mission with better than 90% accuracy.
Complete a mission on Normal difficulty or harder without any marines dying.
Kill 25 drones without friendly fire. Four marines must be present in the mission.
Successfully perform 5 fast reloads in a row.
Roll under a Swarm Ranger projectile.
Heal all 4 marines with a single Heal Beacon.
Complete 2 co-op missions online. Earns a Team Fortress 2 parasite hat.
Successfully perform a fast reload.
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.