More interactivity could be nice, or minor aspects that enrich the walking experience, that make a game feels like a living entity. In my game, I spent 6 minutes of development to add a breath with vapor for the player and a sound. Not necessary, but introduces something visual that feels alive. Even if no one notices it (consciously) is still there. Then, when the player falls down, instead of put a screen or a message, I only changed the breath to an altered one. The player knows that the fall had a cost (the flame is lower now).