Really cool demo! I think that it has a lot of potential & I was pretty intrigued by the mirror portal in the good ending.
One thing that I think could be improved upon was the monsters. They were pretty slow, so I didn't feel the need to fight them off at all. I think that including a variety of different enemies would benefit the gameplay.
I really liked how the setting & situation was introduced though. The chase scene in the beginning was really strong & helped me become immersed within the world.
Overall, I can really see this becoming something really cool in the future. Great job & I can't wait to see the full game! :)