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