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