Here is the full list of all 9 The Winter Tower achievements.
Failed to enter the Winter Tower.
Had forgotten to bring the Ring from the castle.
Failed to dodge the assault by a feral wolf.
Failed to dodge the assault by an Armaursus.
Mistook a Knight for an Assassin.
Mistook an assassin for a Knight.
Handed Alexis the wrong item instead.
Succeeded the Lord of the House.
Had a mutual exchange of hearts.