Full list of all 12 A Kingdom for Keflings achievements worth 200 gamerscore. It takes around 8-10 hours to unlock all of the achievements on Xbox 360.
Collected 10 unique player banners from other giants during Xbox LIVE play
Reached a total Kefling population of 30 (Single Player)
Build a cathedral (Single Player)
Played in an online game where 20 different player banners appear
Built a glorious statue of oneself (Single Player)
Finished a complete castle with three connected parts (Single Player)
Encountered every possible Kefling hat (Single Player)
Unlocked 25 blueprints (Single Player)
Built a building made of more than 8 pieces (Single Player)
Built a lumbermill (Single Player)
Became the big bully of the village (Single Player)
Trained a Kefling (Single Player)