Magma caverns - this was a good concept with bad implementation. Running from rising lava? Good. Using level wrap to do so? Interesting. Does the level use both to good effect? Sadly, no. See global problems below for more info.

The Factory - See global problems below for more info.

Spike Palace - See global problems below for more info.

Snow tomb - This was another decent concept gone wrong. An icy cave with lethal...inverted lava. That alone was part of the problem. Most of the enemies used here just look too bizarre with their colors inverted. Also, with the backdrop being so shockingly white, it made the whole level blend together (in a bad way). Foreground and background contrast is important in platformers, since the player needs to be able to distinguish important elements (like enemies) from their surroundings. See global problems below for more info.

Funklen Forest - waaaay too busy. The sheer amount of background clutter in this stage is just overwhelming. It distracts from the numerous enemies, which is a big problem because they're frickin' everywhere. See global problems below for more info.

Global Problems
These are issues that all of the above levels pretty much share, so I figured I'd cover them together.

First, about your levels' structure...they feel raw. Like, the tile sets are used correctly and all that, but the place they come together to build doesn't feel right. It doesn't look like a place that could actually exist. It's more like a fabricated obstacle course. They have no atmosphere and illicit no feeling, because everything about their construction is just too unnatural. Granted, Mario is a fantasy world, but you still need a degree of suspension of disbelief. These stages pull you out and remind you "hey, you're playing a platformer", because they're constructed more to be challenging and troublesome than they are to create a setting. A good level needs to do both.

Next, the challenge factor itself: I'm a darn good SMBX player, and sometimes even I have trouble in your levels. The term 'romhack' comes to mind. Objects and enemies are thrown together to make the stage more difficult while ignoring any sense of aesthetics or reason. There are few breaks in between the challenges; either too short or non-existent. A level shouldn't be in the player's face with threats from start to finish. That'll just exhaust them and make them want to quit. It's okay to make a hard stage, but you have to pace it properly.

Lastly, the variety of the challenges. Your levels tend to delve into it too much. For example, in Magma Caverns, you had some enemies that made sense to be there. Swoopers, and to a lesser extent, Lava Lotuses. But you also had Thwomps, Roto-Discs, Bullet Bills; even the side room had enemies wandering around in it. There is such a thing as too much variety, and unfortunately, SMBX offers the developer a lot. You need to recognize where to draw the line. Pick a style for the level that suits it. Pick an enemy set and stick with it. Don't use something just to use it; use it if it makes sense and adds to the level. Otherwise, it only creates more incoherency.

These three problems come together and bring down your levels in a huge way. There isn't one level you asked about that isn't affected by at least two of them. It's a lot to think about, but I hope you understood it all.

FEATURED GAME

woooot!

Congrats to Hali and everyone else who made the levels that stood out from the crowd.

I've only one mediocre level in this game. Hooray for riding on coattails!

Yay! All that hard work has paid off.

Let's just hope it's not an April Fools joke :3

author=Solitayre
Speaking of which, we need somebody to review this one.

Ask Minus to do it.

author=Isrieri

author=Solitayre
Speaking of which, we need somebody to review this one.

Ask Minus to do it.

Okay, but then one of y'all needs to review TTBros and Solitayre gets Makerscore for both.

I wonder, I was taking a look at Hali's post regarding seiromem's levels, and I wonder why the majority of my submissions didn't make it.

Then again, Lakitu's Playground, at that point, was probably the only level I've submitted that actually played and felt like a Mario level.