Alright, so I checked it out and here's some feedback for the game: 

• It would be cool if the box would disappear once you are done with the text. It would look nicer (in my opinion)
• Make your UI text bigger (and maybe choose a more fitting font)
• The jump should be quicker, a quick up and down, like in Mario Bros., unless there is a reason for him to levitate off the ground.
• Some feedback for the player that they are hitting the skeleton is necessary. Currently it doesn't look like you are damaging the skeleton because the animation of the sword attack looks like it is not reaching the enemy and because the skeleton doesn't react to the attacks.
• It is hard to get invested in the story because the writing is hard to process. It doesn't really flow and the sentences read as if they are being cut off too soon. One way to fix that would be to avoid using the same word twice in a short time, like here for example: "...kingdom by the name of Raltath. Raltath wasn't the..." You could simply start the next sentence with "It wasn't the...", and you should combine this sentence with the following one. Generally try to avoid starting sentences with "But". One way you can give yourself immediate feedback is just reading what you wrote to yourself aloud. If it sounds like someone telling a story as they would in real life, that's what you want to shoot for (at first). Also, read a lot! That helps improve all things writing (apart from actually writing).  

And now some feedback for the demo itself: 

It is very short. Too short! A demo should showcase what your game is about, the game mechanics and entice players to come back. However, this one is very short and, I personally, could not get invested and I don't know what the game's mechanics are. You mention a showcase of a concept, but what is the concept actually? Is it an RPG or a platformer? What do you do in the rest of the game?   etc.  There are many questions left unanswered in this demo, and it would greatly benefit by you providing this information somewhere. I wouldn't even mind it that much, but it feels very cash-grabby to ask for backing and donations when you show so little of the game. 

Hope that this helps