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