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