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