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