Here is the full list of all 40 Atom Zombie Smasher achievements.
Survive the night.
Rescue everyone in a mission.
Destroy a Mega Zed.
Complete a level-3 outbreak mission.
Get 100 artillery kills in a mission.
Rescue 100 people in a mission.
Destroy all Zed in a mission.
Unlock all the vignettes.
Complete the campaign.
Accrue 10,000 sniper kills.
Rescue 40 or more people in one helicopter pickup.
Accrue 10,000 infantry kills.
Accrue 10,000 artillery kills.
Accrue 10,000 landmine kills.
Accrue 10,000 dynamite kills.
Launch 500 Llama Bombs.
Cleanse four Zed territories with one Llama Bomb.
Complete a campaign with the Triplets modifier.
Complete a campaign with the Hardcore and Permadeath modifier.
Complete a 20,000 point campaign.
Accrue 500 gold medals.
Purchase a Llama Bomb.
Rescue 200 people in a mission.
Rescue 300 people in a mission.
Complete a mission under 30 seconds.
Rescue 100,000 people.
Rescue 10,000 scientists.
Complete a level-4 outbreak mission.
Use snipers to destroy 100 Zed in a mission.
Get 100 infantry kills in a mission.
Destroy 50 Zed in one artillery strike.
Destroy 50 Zed in one dynamite explosion.
Destroy 50 Zed in one landmine explosion.
Complete a campaign with the Alt. Spawning modifier.
Get 100 dynamite kills in a mission.
Get 100 landmine kills in a mission.
Complete a mission with 3 players.
Have a merc reach Level 5 veterancy.
Rescue at least 100 people in July.
Defeat Wave 7 in the KringleJammer mini-game.