This hack seems to be full, so it would fit more here
; also, some screenshoots would probably help on calling people's interest to this, but from a regular user that's just a suggestion.
I've played it, and I found it overall good, although I feel the levels need more consistency on what they're about; all of them have an enormous variety of enemies, especially the first one, like if the screens with them were randomly mixed into levels. It would be better if the levels were organized by gimmick (as in, first level is about koopas, second is about lakitus and spinies and so on).
I also felt the levels were getting lazier as I went through them; after the first castle, the levels become really, really short - shouldn't that be about the opposite? The final level has a single room and is even smaller than the first castle, and it didn't feel like a final castle at all (also you should consider fixing the level mode in the final room in both levels, it forces piranha plants and items coming out of question blocks go behind the background).
Your level design was pretty fine on the first levels, but then again, your hack declined after the first world, and this point is no exception. I actually suggest redoing that part from scratch, including the final level.
Aesthetically it was fine, well, it's a vanilla hack, so not much new was done. Some background colors like a pink and an orange there were over your levels were the ones I liked the least. I also didn't like the use of a black BG behind relatively bright mountains in another level; but overall, the colors were used pretty well.
I was going to congratulate you for your neat overworld but then I noticed it's the original one with some edits... Well, I can't blame you for that. It does look good actually, it's just that some events in it would be good.
Yeah, that was a quick review for a hack I played some hours ago, so I could've missed things.
Resumedly, I overall did like it, but I think the levels past the first castle need more work. Hope it was helpful, and I wish you good luck with your projects!