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