Alright, this is my first time judging a level. Well, I'm not a Level Judge, but you get the point.
Firstly, this level NEEDED more swaps. It has good potential, but the fact that it is using the vanilla tileset (except the background), doesn't make it look very good. Swaps aren't required, but you are not using the Vanilla Tileset very well, since there are enemies and backgrounds from about every category.
Secondly, the tanks were just unnecessary and trollish. The first one wouldn't be so bad if there wasn't a Bomb-omb right there, which is near guaranteed to hit/kill you. The second one is near-impossible without the Ice Flower, since the tank is a hair too high. The third one is just pointless and unneeded.
Thirdly, the part with the switch was stupid. You just hit the switch, wait for the Parakoopas to fall in the lava, and continue on. Unneeded area.
Fourthly, the boss fight. It's main flaw was that the ceiling was too low, causing Bowser to land near immediately. I couldn't get past that part without cheats. And not a single gimmick! (and no, those things that protect mother brain are not gimmicks)
Fifthly, in the area with all the ladders, there is so many SMB3 throwable blocks, but so few NPCs.
Sixthly, why did you bother putting that Bonus section? It's impossible to get to without cheats/level settings.
Seventhly, why did you need to put that invisible block in the beginning? It serves no purpose.
Eightly, so much clash. SO. MUCH.
Ninethly, you had too much of a variety of NPCs. You have SMB3 and SMW Ice Flowers in blocks, SMW Red and SMB1 Green Parakoopas, and so on.
Tenthly, cutoff.
Eleventhly, how are we supposed to know about that first Yoshi coin?
Twelthly, you put Swoopers in very trollish locations.
Thirteenthly, a very odd overuse of SMW platform-turn-arounds backgrounds or whatever you call them.
Fourteenthly, I looked around a bit in the Editor, and I noticed some random tanks on top of the castle. Why did you even bother?
Fifteenthly, clash.
Sixteenthly, clash.
I can go on and on. This level is very bad in my opinion. Did I say very bad? I meant horrible.
Not to mention, this level is really hard! I couldn't get past it without using a Super Mushroom in the beginning.
Also, what on earth is going on here?