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