Here is the full list of all 46 Trash Squad achievements.
Unlock 3 skins for each of 10 characters.
Complete the game in Elite mode.
Collect seeds playing as Mud Thing.
Unlock 3 skins for each of 5 characters.
Unlock 15 character skins.
Kill 10000 monsters.
Unlock 10 character skins.
Complete the game in Nightmare mode.
Achieve rank 2.
Hire 35 mercenaries.
Unlock 7 character skins.
Unlock 8 characters.
Kill 40 mini bosses.
Destroy 1200 elements not including walls.
Kill 5000 monsters.
Unlock 3 skins for a single character.
Complete the game in Horde mode.
Unlock 3 character skins.
Complete the game in Cannonade mode.
Kill 50 bosses.
Hire 15 mercenaries.
Collect robot parts playing as Welder.
Kill 25 mini bosses.
Open 50 chests.
Destroy 5000 walls.
Destroy 600 elements not including walls.
Kill 30 bosses.
Complete the game in Normal mode.
Destroy 2500 walls.
Kill 25 bosses.
Destroy 400 environment elements except for walls.
Open 30 chests.
Collect 2000 armour units in total.
Unlock 4 characters.
Kill 1500 monsters.
Hire 5 mercenaries.
Destroy 300 elements not including walls.
Kill 10 mini bosses.
Destroy 600 walls.
Destroy 500 walls.
Kill 1000 monsters.
Open 20 chests.
Kill 5 bosses.
Unlock 1 character.
Kill a chicken in the Composter.
Open 5 chests.