Is there a particular reason your level came with a world map file as well? Anyway, I'm sorry to tell you this, but that level is just a mess. Graphical consistency is nowhere to be found, the placement of blocks and enemies often makes no sense or is counterintuitive, and there is a huge overabundance of powerups.
First of all, the start screen is kind of nice, but why would you make it so that the player can fall off on both sides? The coins galore pipe found almost right after that serves no purpose at all: It's no fun for the player to just be given so many extra lives without having to do anything to deserve them, and in fact, falling down for so long without being able to do anything is just a waste of the player's time. All it managed to accomplish in my case was making the engine's graphical drawing glitch out. The rest of the cave part also forces the player to wait a lot. And having to search for invisible blocks to jump off on a completely plain platform is no fun, especially when it looks like that jump could perhaps be made.
The mushroom section was not extremely exciting, but had some nice ideas that you could have explored further. However, if you place a powerup right after the checkpoint, please make sure that a player restarting from that point can realistically get the mushroom before it falls down into a hole just like that. With the exception of the (rather annoying) squid, the water section is practically devoid of dangers whatsoever, and I could just swim straight through it. The sky section was built around a neat concept, albeit very finicky to get right sometimes. Since the loops the platforms go through are often also rather long, there is a lot of waiting involved again. Also, a few of the Koopas in this section are placed so that they are absolutely no danger to the player. And for some reason I seemed to be unable to hit the block with the Tanooki suit before hitting the switch block of that trail. I sort of phased through the block instead, which almost caused me to fall off the platform. The castle section at the end was mostly okay.
All in all, it very much looks like you just tried to cram every idea and experiment you thought would be cool in theory into one level. Unfortunately, it doesn't really work well in practice. You might be better off taking a step back and only using those parts that are actually enjoyable to play, but trying to expand those to fill a whole level.
Again, sorry for being so harsh. I hope you manage to improve the playablity and fun factor of your level.

After replaying this level, I can assure you that it is most definitely not too short. I see quite a number of improvements from the first version. I only have two complaints any more: Firstly, I like how you addressed the problem of having to jump over fish in water on this screen by adding a vine for the player to use. Still, I would recommend not placing one of the fish directly under the vine, as that makes grabbing and climbing it without taking a hit almost impossible - especially since a ghost is pursuing the player at the same moment, leaving not much time and room to bait the fish with a fake jump. And secondly, it seems to me like the spawn rate on the underwater crab generator right here is still very fast.
Other than that, it's still a challenging but enjoyable level. And let me compliment the beautiful aesthetics again.

This level has definitely improved since the first version, I think. It is much less likely for the player to get totally lost now, and not having to deal with Lakitu is very pleasant.
I still think that the second part of the level (after the checkpoint) goes on for too long, and that some parts of the level are unnecessarily hard to navigate. I am also not a fan of having to search for invisible blocks in order to progress, but at least they are usually not the only way as the player receives items that allow them to fly/float fairly often. This also makes it possible to skip parts of the level by flying past them, though.
One thing that I assume to be a bug: The platforms that fall down upon touch (the ones right above the coins saying "kentona") also begin to drop when the player walks under them on the platforms of solid blocks below. They respawn only if the player moves quite a distance away from them. Is this intentional?
All in all, the level is much more accessible now, but I personally still can't say I found it extremely enjoyable to play.

Definitely a very beautiful level, and most of it very well-designed, too. I will admit that there was a bit too much sliding involved for my tastes, but since there is enough substance to the other parts of the level as well, I can definitely say it's not just an attempt to cover up a lack of content. Some parts of the level were more challenging than others, but generally always fair. I was going to complain about the placement of piranha plant pipes both above and below the trail of the platform you ride in one of the sections, but then I realised you gave the player an unmissable fire flower exactly for this situation. So, well done.
My only critical remarks are that the graphical passability of the rainbow floor threw me off, as it seems like characters are standing in it to a certain extent, rather than on top of it. Also, due to their movement patterns, it can become almost impossible to climb from one platform to the next one in the optional section. Unless, of course, you specifically intended for the player to only be able to get up there by bouncing off Bullet Bills - if that's the case, then never mind.
A good level in pretty much every regard, overall. Nicely done!

A very pretty level with a lot of interesting bits and clever little puzzles to it. The many design concepts that went into this definitely deserve some attention. Unfortunately, there is not that much incentive for the player to try and find all the secrets, and just trying to get to the end of the level isn't that challenging or representative of what this level has to offer overall. This is the kind of stage that others would probably have set up as a red coin level or something similar - with all the risks and problems that come with such a level. As it is now, this level definitely works, but it probably doesn't work entirely as intended. Still, designing something like this is quite the achievement!

There's a lot of vast and open space here - which definitely looks pretty, but also makes the lack of substance even more obvious. It takes a very long time for this level to actually become somewhat interesting, and large parts are devoid of anything remotely challenging. In fact, most of this level hardly requires any real action on the part of the player at all. The cloud jumping section has quite some good bits to offer, but the focus is still very obviously on aesthetics rather than enjoyable gameplay. Also, if possible, I recommend trying to change the mechanics of those trampoline clouds in order to prevent the player from accidentally picking them up.
As a whole, I can see this level's potential, but there isn't much to it at this point yet.