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