Ya shouldn't link ROMs (.smc, or in your case, .sfc). Make an IPS patch
and post that instead.
Having grabbed it though, I gave it a try up to world 1, and the main issue I noticed with this was that your levels ressemble a lot the originals (I think 105 is the biggest instance of this, also the way you placed the bonus rooms in most of the levels). One often good idea is to hit CTRL+Del to start levels from scratch, as well as changing the tileset/music a little to make it feel different.
But other than that, I think you're onto something. For what seems to be blatant edits, it has a very decent amount of thought on the design. As I went on I noticed you started to add a lot of your own spice in the levels. The first castle's second room was a nice example of that. Other than some missing corner tiles here and there, your levels don't seem to have any aesthetical flaws, either.
I might play the next world later on. I wish you good luck with this (and remember to make an IPS patch next time!).