Exit 8 by Inc. Genki Kawamura

Inspired by a cult video game and now adapted into an acclaimed film, Exit 8 is an innovative work of storytelling, and an ingenious locked-room mystery unlike any other.

A young man is riding the Tokyo subway when he receives a life-changing text message from his ex-girlfriend. He exits the train, but extraordinary things begin to happen, and he finds he cannot escape. Why is he trapped? Is it related to the text message he received? Will he solve the clues before it is too late?

The subway will loop endlessly unless he follows precise rules:
Do not overlook any anomalies.
If you find an anomaly, turn back immediately.
If you do not find any anomalies, do not turn back.
GET OUT THROUGH EXIT 8.