Here is the full list of all 29 Rogue Legacy achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Find all blueprints (purchase not necessary).
Beat one of the clown's games at least once.
Beat the game... twice.
Mock the traitor.
Defeat the brothers.
Defeat the last boss.
Defeat the trademarked chemical.
Defeat the asteroids.
Defeat the son.
Defeat the doppleganger.
Defeat the boss in the Maya.
Read the last journal entry.
Defeat the boss in the Land of Darkness.
Play the game for at least 20 hours.
Find all the runes (purchase not necessary).
Use the special class at least once.
Put at least one point in every skill in the manor.
Defeat the boss in the Forest Abkhazia.
Defeat all the minibosses.
Have one rune equipped in every item slot.
Defeat the boss in Castle Hamson.
Reach level 50 or higher.
Have one piece of equipment in every item slot.
Die 20 times or more.
Open your very first gold chest.
Kill a chicken.
Earn your very first Enchantress rune.
Choose a hero with no traits.
WITHOUT using the Architect, complete the game dying 15 times or less