You nailed the main scene (Whitewalkers climbing the ice wall), but you missed the key stylistic requirement: 'in the style of Game of Thrones,' which strongly affects the look and mood.

You nailed the main scene (Whitewalkers climbing an ice wall), but you missed the key instruction that it should be in the Game of Thrones style. The added 'signs of a battle' changes the focus slightly from the original.