So I've been playing you're episode because I was surprised to see that someone actually made another wario land (for SMBX, not an actual game). I've been playing this also because I wanted to see how it holds up and whether or not I can consider it an addition to my Wario Land Duology.
First and foremost, the story - It had some potential, but it felt nonexistent for the entirety of the episode. Of course I know this is supposed to be structured just like Kirby's Dreamland 3 for SNES and not many people care for story in a series like Kirby, but I'd like to see some new things done to make the story feel more like a quest, like every once in a while, you fight a character who is sided with Dark Matter and he/she wants to kill you before you can get to the source of all evil. Sometimes, recreation needs some more to it than just copying and pasting something. It's just a suggestion mind you.
Now, the levels - So many of these levels are just bland, filled with too many gimmicks, have questionable design choices, or are just intrusive. There's not many areas with BGOs and it makes the levels feel empty so I would suggest adding some more to make the levels look better. Another big problem is the enemies. Not only is there little variety, there's spots where there's way too many of them, and sometimes there would be enemies spawning right at my position when I don't see it coming so you should fix that issue. The biggest sin of this episode is not only are most of the levels really long, none of them have checkpoints. I was able to fix this issue by putting the .lvl extension for the warp leading to a level so it would be best to do that when you have an episode that doesn't feature a world map. This is why I keep starting at the same spot in the hub world, which by the way is not only bland, it also looks terrible. I especially harp on the gimmicks most of the levels have because they're used to get through the level, much like having an ability to destroy this block only to hit a switch, or hitting a cluster of goombas to find the ones that are switches, which is really not a good idea at all. The one I hate the most is the Tanooki blocks, where I have to turn into a statue in order to see the blocks. It just came off as intrusive as there were areas where these blocks were blocking my way even when I was in danger. The key doors are also a problem, and like the last two gimmicks, this is way too abundant. All these gimmicks do is just make the episode so repetitive. On top of that, when ever I need an ability that I feel will help me, it's not even there. Sometimes, I get an ability that I don't want right as soon as I enter a door or are right in front of it. Why exactly would you do that? There is no reason for anyone to be forced to have an ability that they don't want. For example, if I have a hammer suit and I enter the door, only to get a fire flower, which I didn't want BTW, then what was the point of having the hammer suit in the previous section anyway if I can't have it for the next section? You shouldn't do that EVER! That is not good design, especially considering that you spam power ups in some areas. You even have the player use them to get through the level, combining this with the other gimmicks you overused. By the way, there was just the final boss in the final world, the Hyper Zone, and it had absolutely no other levels so that's the only inaccuracy you've made.
Of all the levels, I think Cloudy Park 2 is the worst level in the whole game. The gist of it is the player has to hit the switches at the end of each section of the level. Now that may not be so bad... until I realized I had to hit all the switches in every section. If I didn't hit one, that means I can't backtrack until I get to a warp that takes me back to the beginning. The even worse part is that all of the "!" blocks have power ups, meaning if I used them all up, I won't have any power ups period. Like I said, you use this gimmick of hitting colored switches WAY to much, and the same goes for the Tanooki blocks and the key doors. Another level is Hyper Zone 2, where there is SIX keys, and I have to be honest, you seriously got carried away with this gimmick. When you design a level that revolves around platforming, don't have so many gimmicks. Keep them as minimal as possible. The final level, Hyper Zone 6, is the most sinful of all. It's long, full of all the repetitive shit you've had through out the episode, not to mention NO CHECKPOINT!!! That means if I died, I have to start from the beginning (had that happen to me only because the game crashed on me at one point). I also noticed in one section of this level where I have to destroy blocks with a hammer suit, the hammer suit power ups are in blocks and don't spawn from a warp. So if lost both of them in the section when I have to backtrack, I won't be able to break those blocks because I don't have the hammer suit. I don't know if you accidentally overlooked this problem, but if the player has to backtrack to a specific spot with a power up, have it spawn from a generator.
The bosses - The mini bosses are just dull, and be quite honest, one mini boss had too many phases, making it feel like a boss battle that just drags on. Now as for the major bosses, I'll just make a list of things that I want to say about each of them.
Whispy Woods: A pretty boring boss and it has some issues, much like the bouncing apples not spawning again after I killed them. I would suggest generating them at 3 sec increments and it'll work out.
Dark Painter: You can stand on the cars and get hurt by them! I was constantly flung away because of this, disallowing me to hit the boss with the bombs. Don't make the projectile so fast either. It's harder to avoid like someone shooting a gun.
Mr. Bright & Mr. Shine: Literally this is a hassle because Mr. Shine is SMB1 Bowser and Mr. Bright is SMB3 Bowser. This is the most intrusive bosses I've faced. There are too many projectiles to avoid, thus I lose a useful power up and have to stick with the Maple Leaf. Not to mention, I have to throw bombs at Mr. Bright (in fact, 20 bombs) and it makes the boss more painful to fight than it already is.
Ado: A cool concept, I'll admit, and it isn't really as bad as I thought. It just goes on for way longer than needed. That means if I die, I have to start the fight all over again, and I absolutely hate that very much. Maybe you could make the level a bit larger so the player can avoid the bosses' projectiles. Otherwise, pretty decent boss.
King Dedede: First off, why does he transform from KDL3 Dedede to KSS Dedede? Second, the sprite mask on Dedede's hammer looks screwed up. Plus, you didn't even bother replacing the default effect for SMB1 and SMB3 Bowser Dedede. Besides that, this boss isn't as bad either.
Dark Matter: This is atrocious. Without Yoshi, you mind as well just say "You're fucked!" With Yoshi, however, it's a cake walk. The second phase isn't any better. Anticlimactic and just poorly executed. The rinkas get out of sync and make things even more hectic.
Overall: These bosses need some work. Just fix the issues I explained and the bosses will be a bit more bareable.
The graphics - I noticed that you used some of my recolored npcs, as well as some custom made sprites by me and other people, which I hope you gave credit to. While some Backgrounds were pretty to look at, most of them look like they were done in MS Paint, which is not the best software to use when making custom graphics. Even some of the BGOs look like they were done in MS Paint. I kind of wished there was a more visually diverse cast of enemies; enemies that fit the theme of the world, minions of the villain, that kind of stuff. It's just a minor thing though. Just make your custom graphics in Paint.NET, give them some cleaning, and everything will look good.
Overall - This is pretty disappointing. There's a load of flaws that you can fix to make this episode salvageable. I'd like to say though it is harmless since I wasn't involved in this and that I assume you're new to SMBX. If you can fix every problem that I pointed out, then this episode might just be good or possibly better. I will not be adding this to my Wario Land Duology as it would leave a bad stain on the series.