Here is the full list of all 32 Castle achievements.
Acquire all the trophies of the Wall of Fame.
Make 100,000 points in the Protect the Castle mode
Complete the Protect the Castle mode
Put 200 Golden Blues to sleep
Complete the Humble Builder mode
Get rid of 200 Burrholes
Complete the game in Normal mode
Prevent 200 bomb explosions
Put 50 Golden Blues to sleep
Roast 200 Poulthieves
Extinguish 200 castle fires
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)
Send 100 Silver Reds to the land of dreams
Fix 100 Clorm damage
Prevent 50 bomb explosions
Get rid of 50 Burrholes
Fail 10 times
Prevent 20 bomb explosions
Get rid of 20 Burrholes
Roast 50 Poulthieves
Buy everything from the shop (max. upgrades + max. items)
Extinguish 50 castle fires
Send 25 Silver Reds to the land of dreams
Complete Level 12 in Normal Mode
Extinguish 20 castle fires
Roast 20 Poulthieves
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