Full list of all 14 Battle Islands achievements worth 1,000 gamerscore. It takes around 60-80 hours to unlock all of the achievements on Xbox One.
Garrison 500 army units
Attain 100 offensive victories against the enemy
Loot 2500000 supplies from the enemy
Attain 10 consecutive victories against the enemy
Attain 45 stars in the campaign
Upgrade a supply depot to rank 10
Upgrade command bunker to rank 8
Lose 500 riflemen in battle
Promote the bomber in the command bunker
Expand your base to 4 islands
Promote the warship in the command bunker
Remove 8 obstacles from your islands
Complete the tutorial
Acquire 2500 dog tags from the enemy