Slender: The Arrival
20 Achievements
400
8-10h
Xbox 360
Xbox One
Xbox Series
The Collector I
Find all numbered letters
30
How to unlock the The Collector I achievement in Slender: The Arrival - Definitive Guide
There are a total of 13 Numbered letters in the game. Please see The Collector II for more information and a video with all collectibles in the order they appear in the game.