Very short VN, not much to say about it since it's so short, drawing style is pretty unique, dialogue has exposition that isn't relevant to the story like knowing the map of the kingdom and exposition that could be better told by the story itself like the tradition of the moonstone. Instead of dumping it on the player you can just explain it bit by bit, a couple of lines when the wizard calls you out like: "I can't be selected to carry the moonstone! It should be done by the most talented warrior of the city... which obviously isn't me since I didn't take part in the tournament..." stuff like that. Just my opinion of course.
Game-wise not sure why you didn't go with Ren'Py since the game lacks some quality of life stuff that's included out of the box with it like volume options and text speed options. If you can implement one thing at least please add a text speed option so people who don't like typewriter text can select highest speed. Small bug also, if you click Load in the main menu then Back the game crashes.