Here is the full list of all 27 Garda achievements.
Placing a wall of sand
Fighting the first boss
Placing an emitter
Unlocking the zone of the first artefact
Getting rock using a wisp bomb
Opening a door using a button
Sending soldiers in an excursion
Getting pushed by a mover
Getting the fruit of gods to gain more freshness
Riding a camel
Touching 5 mirages in the dead zone
Unlocking the zone of the second artefact
Getting more than 40 soldiers
Getting all construction plans
Growing plants from moisty sand
Playing with 2 wisps or more on your side
Getting an item turret and a build turret, making them cooperate
Surviving more than 30 seconds while it's the Doom
Fighting the second boss
Finishing the game
Losing against the final creature
Getting the rare death animation
Losing 40 games
Getting a soldiers' chief when coming back from an excursion
Getting 5 soldiers' chiefs
Destroying your totem at wave 42 to anger the gods
Unlocking the zone of the third artefact