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