I really like the UI/Menus, it looks really nice. The level design was kind of difficult, maybe it's not too weird if you're familiar with Mario Maker- which I'm not- but still pretty fun to learn how to traverse them. I will say that the physics is slightly off from what I'm familiar with when comparing it to Mario on NES.
Also, there was a bug where I couldn't jump when I get any power, which was interesting and you should probably investigate that
Other than that, I really kind of like this and I'd like to see what you do with it in future updates