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