Letter is a 2D isometric survival horror game. In the game, you explore different locations, collect keys, documents, therapy tapes, and more. You'll also find various medical items that can be used to fight enemies, but you'll need to be strategic about how and when you use them, because items are scarce.

The story follows a young girl named Lilian. She is living an ordinary life until one day, a letter in her mailbox turns her world upside down. She wakes up on a speeding train with no memory of how she got there or of the letter she was reading.

The game explores themes of mental health and PTSD through surreal environments, fragmented memories, and psychological tension.