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