The The Writer Add-on for Alan Wake has 9 achievements worth 250 gamerscore.
Special 2: Complete the elevator ride.
Special 2: Defeat the final obstacle between you and your goal.
Special 2: Make it through the approach to the lighthouse without firing a weapon.
Special 2: Complete the episode without reloading the game or restarting a checkpoint.
Special 2: Survive the final encounter without being seriously hurt.
Special 2: Make your way past the tornado in under 60 seconds.
Special 2: Discover 10 Night Springs video games.
Special 2: Discover the secret area.
Special 2: Have some poison poured in your ear.