Full list of all 15 Band of Bugs achievements worth 250 gamerscore. It takes around 10-12 hours to unlock all of the achievements in the base game on Xbox 360.
The base game contains 12 achievements worth 200 Gamerscore, and there are 3 DLC packs containing 3 achievements worth 50 Gamerscore.
Froze 50 water tiles
Earned 30 points in a single Spider Hunter game
Won a scenario by knocking all opponents out of playable area
Hosted 10 multiplayer games
Won three multiplayer games
Earned 20 gold medals
Completed the single-player campaign
Showed Barbarians up in food hunt
Used 25 skills or spells
Defeated an opponent by knocking him into the water
Earned five of every hit bonus type outside of the tutorials
Completed the Tutorial
Completed the Red Kingdom downloadable campaign
Earned at least 10 gold medals from downloadable campaigns
Completed the Ninja Sticks of Fury downloadable campaign