Do your best and take your time to find or create some full scenes that match MK's style and feel to add a little more depth to the scene around your character overall. Full existing scenes tend to take way longer to render but can really bring down the house. Your background game is on point and not much suggestion can help there because you have mastered it. This is the only way I can think of to challenge you is to make the background a living 3d scene from time to time without turning your back on your background game also. Good luck! Youre killing it overall!