Eh? Why Am I Gone?

After some weird anomalies, the boy discovered his own body. After losing his consciousness and memory, he met a character he had imagined, and then learned that he might not be dead. He had to trace the cause of his death, regain his body, and kill other selves in his own memories and hallucinations. Along the way, he pried into his past from various scenes, and how he would choose after learning the truth...