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