Just finished reading Summer time Rendering!!! Excellent manga.if

Can somebody explain the ending of Summertime Render to me? Why did Shinpei time travel one last time to a world where everything was okay, nobody was dead, and it seems like

Summer Time Rendering: Another Horizon debut trailer - Gematsu

Summertime Render - 25 (End) and Series Review - Lost in Anime

Summer Time Rendering Manga Series Themed Escape Game Announced, MOSHI MOSHI NIPPON

Summertime Rendering Volume 3 Review - TheOASG

Read Summer Time Render Chapter 87 on Mangakakalot