Here is the full list of all 24 Super Turbo Demon Busters! achievements.
Level up a mercenary 20 times
Kill 2500 monsters
Kill 250 zombies
Complete 50 raids
Kill 1000 enemies
Kill an enemy while your health is at 1%
Kill 100 ghosts
Earn 50,000 credits
Break 50 crates
Level up a mercenary once
Have 10 guns in your arsenal
Earn 5000 credits
Search 150 corpses
Complete your first quest
Kill 25 monsters
Complete your first raid
Kill your first monster
Kill three enemies with a shotgun round
Kill 250 monsters with a machine gun
Kill 5000 monsters
Kill 10,000 enemies
Complete 100 quests
Unlock all mercenaries
Kill 20,000 monsters