The player's score is already being tracked internally with every kill and money bag acquired, so it is something I've planned. I'm not sure if it would be anything more than a method to simply gain more lives. But since the demo does not feature a lives system, I didn't feel a need to showcase the score for now. I have no plans to have an RPG level-up system along the lines of Simon's Quest or Adventure of Link - as EXP-based level means that balancing the game could be trickier and may encourage grinding (which I'm not a general fan of).
But I do plan to feature a wide variety of other kinds of features that are not currently expressed in the demo. My general inclination is towards features that can provide intrinsic value, like certain types of collectibles that expand the world or provide more diverse content and promote exploration -- but I don't want to get ahead of myself with how early in development I am. Just starting small for now.