Isekai Souzou no Susume: Smartphone App de Wakusei wo Tsukutte Shimatta Ore wa Kami to Nari Sekai wo Meguru

A certain middle-aged man, Saito Kenji installed a mysterious smartphone app "" (Isekai Souzou no Susume, "Guide to Creating Another World"). It was a game in which you could freely manipulate planets, lives, tribes, eras, and all sorts of other things. However, as a result of being transferred to the world on the screen through a new function, he found himself able to travel back and forth to Japan! You can explo...