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