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