I would like to begin by saying that this game is a game that shows a lot of promise. The music and sound effects aren't bad, though the music is not yours, I'm aware. The visuals and animations aren't bad and show lots of potential, and the story is pretty good too.
That being said, there are a few problems with this game. Most of them tie back to the lackluster gameplay. Jump height seems random and sometimes I can't double jump. The controls are mildly responsive at best. The hitboxes are strange, and combat feels loose and unresponsive. I personally recommend making every hit seem powerful and impactful. Don't just have enemies flash red. Have them change animation, and reel back. Maybe freeze the screen every time you land a hit. And work on the responsiveness of the controls and such.
Overall, I'm afraid to judge this game too harshly because it's a demo. This could be only a bare bones demo of the most basic features and all of the patches, extra content, bugfixes, and new features are going to be added after release. And that's something a lot of people miss. So I enjoyed your game, and hope it can be everything I think it can. While I can't monetarily support you (Sorry ;( ) I can at least give you that.