It has a neat mechanic and a very fun premise. It makes me wonder how this could be expanded on. Maybe an adventure game where you have to do quests but have to get from place to place? Maybe a sandbox rpg type game? There are so many things you could do with this as a base!
One thing I think could be improved on is how levels (height) are conveyed to the player. It's a bit difficult to tell if something is on a higher platform or not, so some visual indication would be appreciated. Maybe some dithering effect to represent a change in elevation?
Great job!