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.
Finished a complete castle with three connected parts (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)
Encountered every possible Kefling hat (Single Player)
Reached a total Kefling population of 30 (Single Player)
Collected 10 unique player banners from other giants during Xbox LIVE play
Unlocked 25 blueprints (Single Player)
Became the big bully of the village (Single Player)
Built a building made of more than 8 pieces (Single Player)
Built a lumbermill (Single Player)
Trained a Kefling (Single Player)