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 the runes (purchase not necessary).
Find all blueprints (purchase not necessary).
Defeat all the minibosses.
Mock the traitor.
Defeat the brothers.
Beat one of the clown's games at least once.
Defeat the son.
Use the special class at least once.
Defeat the trademarked chemical.
Defeat the asteroids.
Defeat the doppleganger.
Put at least one point in every skill in the manor.
Beat the game... twice.
Defeat the last boss.
Read the last journal entry.
Defeat the boss in the Land of Darkness.
Defeat the boss in the Maya.
Have one rune equipped in every item slot.
Defeat the boss in the Forest Abkhazia.
Reach level 50 or higher.
Open your very first gold chest.
Have one piece of equipment in every item slot.
Defeat the boss in Castle Hamson.
Die 20 times or more.
Kill a chicken.
Earn your very first Enchantress rune.
Choose a hero with no traits.