My Review:
Atmosphere [4/5]
Yes, a grass level. That was really all that I took from the level. I didn't see any elements that really spoke to me as being designed by your specific standards. But given it is "A Simple Level" I can't really complain, but it didn't leave a long-lasting impression as well.
Level Design [2/5]
For one, there is no midpoint whatsoever. The red coins are in nice spots, but the player doesn't exactly have a means to reach a few of them without putting themselves in instant death pits or running around looking for an invisible block with no indication whatsoever. Then there's the pipe where the Red Coin's death event activates: the pipe out spits you almost to the beginning of the entire level. This means that if the player didn't care about Red Coins and just wanted to see what this random pipe was...then they are punished by having the replay 90% of the level again.
Lastly, the level itself is pretty linear. With the DarkMatt concept of "Hold right and occasionally jump" method ringing true here.
Graphical Continuity [2/5]
Pick a game style and stick with it. SMW tiles, SMB3 Tiles, SMW Enemies, SMB3 Enemies, SMW Background, SMW Blocks & Coins, SMW BGOs, SMB3 BGOs and finally a moving pipe that doesnt extend to the bottom of the screen creating huge cutoff.
I know clash is something people hate to hear, but if it exists than it can't be disregarded. Pick one type of graphical style and stick with it, otherwise you have a mix-mash of just..everything.
BGO Placement [3/5]
One point is deducted from mixing two different styles of grass hills.
The more important point taken away is from the lack of a long-lasting impression. While writing this section I had to check the level two times just to refresh my memory if BGOs were even used. I recommend trying to use trees or maybe having a forest sub-section instead of a cave section. This way things some seem to flow inconsistently.
NPC Placement [5/5]
As much as I would like to find something wrong in this field, I legitimately cant. While NPCs were used very sparingly, I would have to say they were used rather well. I would highly recommend you try to expand your experimentation with NPC usage since you do seem to get the right idea on where and when to use an npc, although rather sparingly like I said.
Difficulty / Replayability [1/5]
Sadly, due to the incredibly linear aspect and lack of a long-lasting impression this level made I would rule this to be rather low in terms of replayability. Now, this doesn't mean someone should avoid this level, that isn't true. This level is perfect for a World 1 level, but its too straightforward by common SMBX Designer standards and leaves nothing to the imagination or leaves an impression afterwards.
Great experimentation level, but you should expand on a less linear design and try to stick to just one type of graphical style.
[Extra] I do have to give you kudos however. I RARELY see a purely vanilla level, which I must give you props for. Nowadays everyone uses at least a custom soundtrack; whereas this level went completely pure.
Overall Score: 17/30
Final Score: 5.6/10
Judgement: Average
Video:
https://www.youtube.com/watch?v=yTpwp-20KGs