Tip: When determining a time limit, remember that players won't be as familiar with the level as you are. If you normally complete the level with the timer around 100, others might run out of time on their first try.
My second hack. Anyways, this hack features ExGFX, custom music, ASM, and more.
Plot: Time and time again, Bowser has been defeated by Mario. However, one day, Bowser has discovered a gem that he plans to use to take over the Mushroom Kingdom. Meanwhile, A toad found a letter from Bowser, and told Mario. Mario, mad, and angry, has decided to defeat Bowser once and for all!
(It's sorta a take on my plot from my older hack. As this hack is meant to replace the Final Showdown.)
You can watch the trailer here: https://www.youtube.com/watch?v=DQtOcCOFjV4
Your hack is a pretty fun hack.
But the levels don't stand out so much, they're good, but not too memorable (it's just that they feel like I already played them somewhere else). The levels standing out are Back to the Past, for being really different, Foggy Grasslands and Coral Lake, but still, I don't think you need to change. I just hope you play around more with different ExGFX, the reason some levels feel "same-y" it's because the repeat the similar Redrawn SMW Graphics too much (which is already used in too many hacks).
But that's just a little tip, don't worry about that too much.
Oh, and another thing, the first fortress on this game is harder than any other level, and it's almost impossible to beat that Thwomp without feathers, I don't think you need to change it, but I recommend you placing this fortress in another world later, it would make the difficult curve better without changing the level itself (which is actually good, due to the challenge).
I really like the title screen too, it's cool.
Your hack somehow reminds me of Mario Gives Up 2, at least in some aesthetics and musical choices.
The letters on the title screen aren't very well made. Those letters are heavily pillow shaded and that is extremely harmful for you and your hack ): It would be great if you fixed it. What is pillow shading?