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