This level is kinda eh. Sure, it uses SMB1's style while most levels use SMB3's style, but style won't make a level stand out; design does, and this level's design is about as average as SMBX levels can get. While the block placement is well done, the NPCs hardly ever vary from the standard Goombas, Koopas, Piranha Plants, and occasional Venus Fire Trap (the water enemies don't count since almost all of them are out of the player's way). There's also a pipe that's blocked by frozen coins, but its so early in the level that there's no fire flower beforehand, meaning the player will have to backtrack to get in the pipe (and it only leads to a dragon coin).
Also, there's this:
Why did you use so many foreground images here? On top of making the level really annoying since it's a challenge just to see what's where, it causes SMBX to lag severely.

Summary:
GOOD:
-Graphics aren't terrible.
-Music fits the level.
-Block placement is okay.
BAD:
-Little NPC variation.
-Waterfall spam.
In conclusion: while the level isn't bad, it's not very good either. I'd say this deserves a 5.5/10.