Here is the full list of all 44 Viking Brothers 3 achievements.
For gathering 100 units of gold.
For gathering 100 units of stone.
For giving the Vikings five tasks at once.
For giving Vikings 300 tasks.
For canceling a task.
For gathering 100 units of wood.
For earning one star on one level.
For gathering 100 units of food.
For using the running booster 10 times.
For using a booster.
For earning three stars on one level.
For using a booster 100 times.
For gathering 500 units of food.
For gathering 1,000 units of food.
For gathering 500 units of wood.
For gathering 1,000 units of wood.
For gathering 500 units of stone.
For gathering 1,000 units of stone.
For gathering 500 units of gold.
For gathering 1,000 units of gold.
For earning three stars on 10 levels.
For earning three stars on 30 levels.
For building 30 buildings.
For upgrading 30 buildings.
For canceling 30 tasks.
For not clicking the mouse for 30 seconds.
For completing a level without using a booster.
For exchanging gold for mana.
For exchanging gold for mana 10 times.
For exchanging gold for mana 50 times.
For encountering a patrolling enemy.
For encountering 30 patrolling enemies.
For destroying an enemy tower.
For earning every achievement.
For unlocking a tavern.
For unlocking five taverns in the main adventure.
For earning three stars while playing Chipmaster.
For finding Thor's hammer.
For finding Heimdall's sword.
For finding Odin's spear.
For finding the three Places of Power.
For fixing the Rainbow Bridge.
For helping the gods in the final battle.
For acquiring the Travel Amulet.