Pretty good level. Although when you start off the level you get an SMB3 mushroom if you're small because of the SMB3 leaf which seems out of place since the rest of the level is SMB1. It's not too easy, and not too hard, and would make a good World 2 or 3 level. Keep doing what you're doing but take into consideration what DinoKing said above, and pay a bit more attention to detail.
*sip* Don't talk to me until I've had my morning coffee.
Level Design and Gameplay (weighed 70%): 4.9/10
This level was quite well done overall. It had a good spread of BGOs and there weren't very many parts that seemed overly clustered or overworked. The level was very linear and played quite nicely to the SMB1 style overall. Even though it provided some good variety, it still seemed to drag on for a bit too long. The amount of variety there was in terms of some elements was a bit too much though. There were some NPCs, such as Cheep Cheeps, that were used too briefly, as well as many others (lava as another main one), resulting in it feeling a bit too busy. The poisonous mushrooms also seemed a little overused and there placement wasn't great. Furthermore, there were issues with warp placement and Piranha Plants placed overtop of warps as mentioned above. One last thing to mention would be coin placement; although the level didn't seem to empty of them, their chosen positions didn't seem great. They were really just scattered about and didn't have great placement overall. The bonus section also seemed like a bit of a tease since there were really just some coins.
Graphics and Sounds (weighed 30%): 6.8/10
It was nice to see a level without too many custom graphics. It really kept to the classic SMB1 feel in this way because of it. There was still a bit of cutoff in a few places however, although it wasn't really obvious. My biggest issue with this level was the music choices. They just seemed a little too over-the-top per se; I think it would have had a way better effect on the overall atmosphere and impression of the level to use simpler music choices, instead of upbeat, funky ones.