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