Kanojo, Okarishimasu ～Suiheisen to Mizugi no Kanojo～

Become Kinoshita Kazuya, a worthless college student at a Tokyo university, and live the part-time job lifestyle on Enoshima with charming heroines Mizuhara Chizuru, Sarashina Ruka, Sakurasawa Sumi, and Yaemori Mini in this game-original story. By viewing all endings, you can witness Nanami Mami's story.

An Original Story Set in the Summer on the Island of Enoshima.
Experience an original love story that could have occurred during the anime's third season. Kazuya gathered the funds to shoot a movie starring Chizuru via crowdfunding, but it was not enough! To make up for the insufficient funds, Kazuya stays on the island of Enoshima for the summer, working part-time with the four heroines. It will be impossible for something not to happen while under the same roof—Kazuya's delusions are in full effect!

[Edited from Gematsu]