The story at the beginning was really good. As good as any start of a well thought out novel that professionals have worked on. I think the game could rely on the story and develop further. Artwork doesn't need to be better if the story is interesting. I got aware of that the choices of text conversations matter little to which ending you get. Instead it seems like the poison determines it but I did not fully explore what trigger which ending you get. I have to admit that I got real frustrated when I played a third time to see if I could get the last medal and ended up trying to kill it again so I did not know how to do. If there was not a medal for all endings I would have thought it was all and stopped there. The path I took the first time was the correct path so I think you did well with the level design.
Oh, and I read now in the description that you can get to the later stages by reloading after completing the game once. I don't know what it means but maybe you could have put it in the game. Though reading the story again was kinda fun.