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