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