Here is the full list of all 42 Viking Heroes 3 achievements.
Used a booster
Used a booster 100 times
Collected 100 units of food
Collected 1000 units of food
Collected 100 units of wood
Collected 1000 units of wood
Collected 100 units of stone
Collected 1000 units of stone
Collected 100 units of gold
Collected 1000 units of gold
Collected 100 units of gems
Collected 1000 units of gems
Completed a level with 3 stars
Completed 10 levels with 3 stars
Completed 30 levels with 3 stars
Canceled a task
Canceled 30 tasks
Completed a level without boosters
Assigned 5 tasks at the same time
Met an enemy patrol
Met an enemy patrol 15 times
Got access to a tavern
Got access to five taverns
Made 50 transformations at a Stonehenge
Cooked soup 25 times
Fired 2 shots from the catapult
Met old friends
Talked to the blacksmith's spirit
Created the first magic cage
Met the Dark Valkyrie for the first time
Defeated the leader of the firebirds
Defeated the leader of the blue birds
Defeated the leader of the golden birds
Defeated the leader of the green birds
Found the Red Rainbow Stone
Found the Orange Rainbow Stone
Found the Yellow Rainbow Stone
Found the Green Rainbow Stone
Found the Azure Rainbow Stone
Found the Blue Rainbow Stone
Found the Purple Rainbow Stone
Restored the Bifrost Rainbow Bridge