That was a nice experience.
Let's get to the things I think are debatable because they're more important.
1. I think that the dash ability should do some small damage to the enemies like for example 5HP and if the damage is enough to kill the enemy you should be able to continue dashing through it.
2. I'il be honest - The control scheme for keyboard users is very disappointing for people looking for a good feeling.
3. The story itself feels very weird (kind of boring for my taste). I would personally think of something more unique and interesting.
4. I would say that pixel art games are very common this days and for this one to pop out of the group there should be something unique like for example very neat effects that are happenening often and I can't believe that Im saying that but maybe try adding some bloom (Im still not sure for what exactly look you're going for so remember that's just a suggestion).
YES Im aware that this is a demo but it's always better the point things out in the beginning.
I will definetly follow the developement of this project. For a demo that's impressive. It's worth my 5 star rating.