If I looked with normal eyes, I wouldn't say the project is good - But if you look with developer eyes, you know how hard it is to make something close to yours project.
And if you are a beginner, it's even harder and involves more effort.
So, I will give some suggestions, and probably most of what I cite requires just one or two tweaks in the code. And please don't take me bad, if you consider my suggestions your project will get better.
The general problem about the project is that it's not loyal to the original mario. If that's not really what you intended, sorry. [Yes, I read the title and the part which says "remix". ]
First of all, at the menu screen, the font- It has a black background, and the letters are too spaced from each other, and that spacing is white. Why? Since you are also using
.tff fonts, this doesn't make much sense.
Then, the fonts, again - You are mixing them and this doesn't look very good. Your "fonts" folder has 16 files - wow. Most projects use two fonts at all, that is, when they don't use a single one! Even if they are a really big project. Of course there's specific exceptions, though. Just like the sprites, fonts helps with the mood of the game - If you used
Comic Sans MS and then a pixelated font(something like
Courier), you know how it would end up.
The sprites - Looks like you mixed sources, that's what I can guess. The tiles are of good quality, but most enemy sprites and related misc are blurred. I also noticed that the images folder there's mixed image types, a small suggestion is that you use only .png for the sake of file size.
The movement - Mario is always running, why? There should be a specific key to enable that, if there's any running at all(which I suggest having). Also, sometimes jumping on enemies will rocket you up. I don't have any suggestions on how to fix this. You can also walk on air. While it's perfectly fine for a video game have air movement, the sprite here is of the walking mario. I suggest a falling mario sprite.
The items - There are a bit too much red mushrooms. There's also no item box.
That's it, I hope I have helped. Good luck!