Here is the full list of all 25 Tiny Troopers achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Beat Chapter 3
Fully Upgrade Your Squad
Kill 50 Enemies with Airstrike
Kill 50 Enemies with Delta Force
Kill 50 Enemies with Machine Gunner
Kill 50 Enemies with Rockets
Collect 10 Medicrates in Zombie level
Revive fallen squad members 10 times in Zombie level
Get a full squad in Zombie level
Kill 100 Zombie chickens
Open a Gate in Zombie level
Kill 50 Enemies with Grenades
Beat Chapter 2
Destroy 10 Tanks
Earn 200,000 Command Points
Destroy 10 Towers
Beat Chapter 1
Collect 25 Dog Tags
Kill 100 Enemies
Use one of each heavy weapon on a single mission
Order 10 items from HQ
Lose 5 Troopers to Mines
Use Airstrike to Kill 3 Enemies At Once
Lose the first mission
Complete the Tutorial