Here is the full list of all 27 Global Outbreak: Doomsday Edition achievements.
Kill 1,000 enemies
Kill 5,000 enemies
Kill 10,000 enemies
Save 10 scientists
Save 30 scientists
Escort 10 soldiers
Escort 30 soldiers
Repair 10 weapons installations
Repair 30 weapons installations
Kill 100 enemies with grenades
Kill 30 enemies with explosive barrels
Earn $1,000,000
Kill 50 zompods in ground missions
Kill 150 zompods in ground missions
Upgrade a soldier to level 20
Win the game
Unlock and fully upgrade all weapons
Reach a 50% XP multiplier
Get 10,000 XP in one mission
Max out a single stats on a soldier
Fully upgrade a weapon
Complete a ground mission on the last meteor using a single soldier
Complete a mission using a single soldier, without taking any damage
Win the game with an hour left on the clock
Win the game with 50% of the population remaining
Win the game without losing a soldier
Be chased by an enemy for 30 seconds