The art is fantastic and the music were all really impressive. It is interesting that you included minigames instead of going pure visual novel. The end of the story did made me sad, can you definitely nailed the writing. I like how you reference the events form the mainline games. One nit pick I would have is that the "critical seija moment" is a bit confusing in terms of presentation goes. Otherwise really good game.
Also do tell me where the OST is, or you have a playlist or something? nvm, saw the game page