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