Tip: Remaking levels from other Mario games is strongly discouraged, especially popular ones (World 1-1 from SMB or SMB3, for example), as their over-presence in Mario games, official or not, often makes them uninteresting to play.
The design is well managed. Sometimes it felt repetitive, like, you have to do the same things in multiple levels (like finding a springboard and using it to jump over an obstacle), but it was okay. Some parts were also a bit too empty, like in the castle, in the beginning of the room where the midway point is. Not much more to say about this hack, since it's a pretty traditional one mostly.
Aesthetics also follow what a traditional vanilla hack is. No shenanigans with Map16, nor custom palettes. Just pure vanilla.
Overall, it was okay. A tad repetitive, but it works for some fun. 3/5.