Here is the full list of all 20 Super Trench Attack 2 achievements.
Have nine members on your squad
Beat the tutorial mission
Perform a double kill
Perform a triple kill
Get an epic bonus!
Beat the game on training mode
Beat the game on normal mode
Beat the game on hard mode
Kill ten ducks during a hunt event
Win 200 Gold during a blackjack event
Win an Epic battle only using defend
Win an Epic battle only using grenades and mortars
Win an Epic battle only using pistols
Get a squad member to lvl13
Unlock all of Ada's layouts
Unlock all of Marie's layouts
Unlock all of Adele's layouts
Unlock all of Bella's layouts
Have over 1500 food at one time
Have over 1500 gold at one time