It is very cute, I think you have used all of your assets well. I was floating around 40 fps, I haven't published anything yet to the playstore so I don't know if that is standard but if you could improve the fps somehow it would definitely improve the overall experience.
There is a couple of things that you could add that made the original mario feel more responsive. One of these is the speed run (perhaps you could adapt it to yours that after you have been walking in the same direction for a couple of seconds toby starts to speed up a little bit).
The second is the jump, the original mario had a great feature where you could tap the jump button for a hop or alternatively hold the jump button down to get as high as possible. I think a lot of people also felt that flailing the controller into the air as you jumped helped also but I don't recommend you add that to yours
All in all its looking very good.