I feel like this is a good, like, start of a start. Obviously this needs a lot more time and effort put into it, but this could be something really awesome.
I imagine some kind of creative back-story to it too, and maybe a more charming, more complex design for the main skeleton character. The orb he's working with could have significance too, if you so desired.
As for the gameplay, like you said, it's a prototype, and it obviously feels that way. When I played the orb came and went at weird times, even when I was pretty sure it was supposed to stay on screen. I see potential for some good puzzles here, but obviously they need some more challenge without sacrificing sense. If you can have the orb all the time, then then the most I can see you doing with puzzles is basically making it a "scary maze" like ordeal where the path to open the door gets thinner and thinner as you go along, but if it just appears and disappears at random times, then that just doesn't make sense. Maybe there are only certain times when you can summon it, like with special portals, or heck, if you have it with you all the time, make it to where the skeleton and the orb have to work together in order to open a door (like, have the orb activate one door and the skeleton have to jump to activate another switch to open that door)
That's all I can think of for now. Keep working, I feel like you could make something with this.