Beat you to it again, bossedit
Green Hill Zone
GFX: 7/10
I was actually mildly surprised by this level. The graphics were really nice, everything was (of course) in the style of Sonic, and I especially liked what you did with the little "molds" in the ground to make it look a bit three-dimensional. There was scenery, there were custom enemies, the only thing that bothered me a bit about the graphics was the background because it was not the Green Hill Zone background
But at least it was SMB3 styled, and SMB3 seems to generally blend well with Sonic's style, so no clash. Really good.
Music: 8/10
The music actually really surprised me. I thought you would use the normal Green Hill Zone theme, but instead you used the remixed version from Sonic Generations! The remixed version has a background beat added to it and is a complete remix from the bridge onward, which made it much more lively and upbeat!
NPCs: 4/10
There were a few different kind of Sonic enemies, of course, and I think that was really okay.
There were I think three mushrooms in this level, and over all it was really easy, so I think one mushroom in the beginning would've been enough. Also there is a midway point that also gives you a mushroom if you need it, so it's actually almost 4 mushrooms, which, for this level is more than enough.
Gameplay: 4/10
This was a solid level, but REALLY short. I played it through in one and a half minutes without dying once. This would be perfect for the first level of an episode that consists of levels that have SMB3 length, but if it's that short, the midway point really becomes unnecessary. The level is like 10 screens long, and at that difficulty not even a challenge for new players.
There weren't really any gimmicks in this level, at ALL. Maybe add something there, even if it's just moving platforms, (or even a springboard, I really expected to see a Sonic styled springboard at one point!) it makes the level more interesting and more enjoyable to play.
My advice would be to add some more challenges to the level, one or two gimmicks, and make it a little longer (or remove the midway point, it's really unnecessary).
This was a good level for a beginner, and if you follow these tips you will make it into the "Pretty Good" section easily. This level gets a score of 5.75/10, which places it in Average, but TOP PERCENTAGE average.