Here is the full list of all 17 Armored Kitten achievements.
Complete normal difficulty
Complete 9th act
Upgrade money drop amount for 100%
Upgrade enemy drop for 100%
Upgrade speed for 100%
Complete 8th act
Upgrade critical shot for 100%
Upgrade health for 100%
Complete 7th act
Upgrade accuracy for 100%
Complete 6th act
Complete 5th act
Complete 4th act
Complete 3rd act
Complete 2nd act
Complete 1st act
Complete 1st mission