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