Here is the full list of all 32 Castle achievements.
Acquire all the trophies of the Wall of Fame.
Complete the King Mode
Put 200 Golden Blues to sleep
Complete the Protect the Castle mode
Prevent 200 bomb explosions
Extinguish 200 castle fires
Get rid of 200 Burrholes
Put 50 Golden Blues to sleep
Make 100,000 points in the Protect the Castle mode
Roast 200 Poulthieves
Send 100 Silver Reds to the land of dreams
Fix 100 Clorm damage
Put 20 Golden Blues to sleep
Prevent 50 bomb explosions
Extinguish 50 castle fires
Get rid of 50 Burrholes
Complete the game in Normal mode
Roast 50 Poulthieves
Send 25 Silver Reds to the land of dreams
Buy everything from the shop (max. upgrades + max. items)
Complete Level 12 in Normal Mode
Get rid of 20 Burrholes
Prevent 20 bomb explosions
Extinguish 20 castle fires
Roast 20 Poulthieves
Fail 10 times
Fix 25 Clorm damage
Earn a grand total of 50,000$ throughout a game (Money spent in the shop isn't deducted from this)
Send 10 Silver Reds to the land of dreams
Complete the Humble Builder mode
Fix 10 Clorm damage
Complete Level 6 in Normal Mode