Millia -The ending- was made in Ren’py and has multiple endings for you to hunt down that are determined by the choices you make.
Here’s a description of the story:
“The story follows the daily life of Rize who lives in a fantasy world. After a tragic event, the world was cursed by one of its two goddesses. The other goddess tries to prevent the destruction of the world by sacrificing herself over and over again each twenty years.
“Rize inherits the title of goddess guardian after his father passed away. With his carefree personality, he quickly becomes friend with the goddess and they spend a happy childhood with each other. However, as time goes by, the goddess will soon have to sacrifice herself again and it means that she will forget everything about him. Will Rize be able find a way to help the goddess? Let’s get into the role of Rize and see how their story will end.”