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