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