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