I've chosen this one to add to my now six-membered (may there be many more) hack library on my 3DS. This is a very good hack, I must say. You're a god,  Arceus!

_{^{Yes, I did say that because you're nicknamed Arceus.}}

I've played through World 1. Here's what I thought of each course:

W1-1

I like how long and exploratory it is. Played through this one three times because my 3DS's battery decided to disconnect twice, blarg.

W1-2

I always dig W1-2s that aren't cave levels. This one is sorta-kinda underground, but no cave. The secret exit/third Star Coin/Arceus sprite requires you to realize one of the pits isn't an actual pit, which you can derive from the pits found earlier. I also love to just slide around on the slopes!

W1-3

Lol, upside-down mushroom platforms! Because some are hard to reach, I love trying to reach them. The first one spawn some goodies if you reach it, and is best reached with a jump with a Ground Pound Cancel at the peak of the jump. The bonus room with the fast up-and-down mushroom platforms was really challenging!

W1-Tower

_{^{(Why does everyone have to use the same tower theme?...)}}
Really fun, because it reminded me of NSMBW's W1-Tower, which was always chaos playing in multiplayer with a second player. Near the start, I got trolled by a Goomba. The secret exit is a sneaky one again, even though it's hinted at with ONE coin...
Near the end, where there are a lot of big and small pendulum platforms, some Z-fighting occurs between the platforms.
The Bowser Jr. fight was quite challenging! And that's quite the achievement, making NSMB's Bowser Jr. fights challenging!

W1-4

Reminded me of SMW's Forest of Illusion, with the go-behind trees. One gripe: when you exit the bonus room with the P-Switch (which reminded me of vanilla NSMB's W1-4 P-Switch bonus room in a positive way) and go to the right a little, the game will lag in a certain section. Probably because three Wigglers and the reskinned arrow actors (the go-behind trees) are loaded. The game runs full speed again when you reach the pipe and two mini pipes.

W1-A

This course is full of surprises. The P-Switch spawning a coin formation shaped like a Poké Ball, the offscreen Star Coin found by swimming into a current... I tend to like water levels BTW. I'm not one of those people who hate water levels just because 7.8/10 Too much water. (Though SMB's water physics were jank.)

W1-5

The level design reminded me of Newer. Stalactites and stalagmites as spikes is really fun too.

W1-Castle

Reminded me of vanilla W6-Castle. Really challenging, especially the part with the moving blocks above lava and below Thwomps. I can't really say much about Bowser, since his fight is mostly vanilla.

W1-Cannon

So, a speedrun of W1-3? Reminds me of SMG's Speedy Comets and some of SM3DL's Special World courses.

EDIT: Played most of World 2, except W2-A and W2-Cannon because I haven't found W2-3's secret exit yet.

W2-1

So, I guess this world's theme is mushroom desert, nice twist on the forever-World-2 desert.

W2-2

[insert SMG4: Who Let the Chomps Out video here]
Is the trick to get the third Star Coin really to stand on the still-opened Flipper, then spawn a Minishroom from the inventory and jump from the Flipper? Or is there something I'm missing? Also, apparently Spinies can't kill Chomps.

W2-3

Lots of explosions!

W2-4

It starts with up/down shrooms, the second half is nailbiting stretcing/shrinking shrooms.

W2-Tower

Technically not a tower. What are the spinning platforms? A custom actor? The zoomed-out section with lots of spinning platforms and 6-7 Dry Bones lagged the game a lot. Very fun 'tower' nonetheless.

W2-5

We're still in Bowser's territory... spike balls and Fire Bars (which are made of fireballs, so all-in-all lots of balls ) pose a challenge to our portly plumber. The first swingable rope is a little jank: if you swing too high, the lowered ceiling pushes you off the rope. Cost me my Super form.

W2-6

Autoscroller. Really fun usage of trickily small moving platforms.

W2-Castle

The start is iconic, with the scale lift lifting the Goomba from the small space so Mario can 'unalive' it... Though, if you fail and the Goomba doesn't get carried out above the semisolid, there's no way to reset except suiciding into the pit, so maybe make the scale platforms longer so they can extend beyond the walls, so you can reset (or add a reset door). And,  Arceus, you managed to make Goombas of all enemies a lethal threat! Cool!

You're welcome,  Arceus. This evening I'll write a review of W3.