W3-1

Not much to say about it, but I like how the seesaw at the end INdirectly helps you reach the top of the flagpole by helping you reach a floating island from where you can reach the top of the flagpole.

W3-A

Classic pipe maze. Though, it's too confusing, as it's not clear prior to taking them where each connected pipe drops you off. I suggest using the different colours pipe to make this clearer. BTW, how on Earth does the jyotyu water not turn the pipes translucent? A graphical glitch occurs when you enter these water tiles from the side, where splashes are shown at the top or bottom, but I know this cannot be fixed without replacing these particles with an all-alpha texture, which'd affect the splash particles from entering/exiting actor water as well.

W3-2

Slight camera glitch at the beginning; it does a very brief jitter when Mario/Luigi spawns in. If you jump on some track-controlled platforms too early, you can't see where you are until the platform goes down again and you can't jump up anymore, so I suggest adding a P-Switch that activates Blue Coins before the first track-controlled platform in the course.

W3-Tower

At the beginning, there's a red, a blue and a yellow block. Another Pokémon reference, or am I just looking to much into it? Level design reminded me a lot of SMW and the boss fight was like Wendy's in NSMBW/2.

W3-B

Piranha Plant swelling ground jumpscare! Creative uses of swelling ground below spiked ceilings and swelling ground sinking into poison water!

W3-C

Porcupuffers and scale platforms is a good combo, as it adds some more action. Also, this course is a Blue Shell farm and a life farm (Koopa + staircase = immortality. That's how AZ got 3000 years old).

W3-3

Reminds me of that one NSMBW course. Enemies can get clipped inside the ground of the floating islands if the raft takes them through it. To put it in pannenkoek2012's words: "I transported a Scuttlebug into a wall's hitbox". It looks so funny - please never fix this!

W3-Ghost

The moving elements remind me of the ghost house (Chalet of Movement) in my SMBX (TheXTech) episode Hax Bros. Though, I find it a little on the short side, especially with how most of your levels are huge! The fake wall is cool, though, really ghost house-like.

W3-Cannon

Reminded me of NewerDS's W3-Castle. But, lemme be honest... It's bland. Walk right and jump to win. You might want to take a look at NewerDS's W3-Castle for inspo.

W3-Castle

Tough avoiding Crowbers. Most dangerous is not getting hit by them, but accidentally stomping them while hanging on a vine! Bowser chose his castle guardians right, and you need to take your time to avoid the birbs and make it to the boss.
You enhance the bosses by changing the arena instead of the boss. This really works, and with Cheepskipper you need to be careful when jumping on him, or you might fall into the poison water!

EDIT: W4 time!

W4-1

A heads-up: the snow background glitches out for a frame if you grab a Starman, die, activate a switch or clear the course.

I like how the pipe from which you enter the P-Switch bonus room is partly 'behind' the chocolate wall. When you exit the bonus room, you land on a Snow Spike, which is a nice detail that reminds me of NewerDS's W2-3, where in one view you spawn Ground Pounding a Koopa, sending its shell forward, it taking down some Piranha Plants.
The pole-swinging is really enjoyable as Mini Mario!
In the secret exit room, if you jump into the hole you spawned from jumping, you die. Better call Saul add a semisolid.
I cleared this course with 420 on the timer once.

W4-2

A fun underground pipe course because it has both horizontality and verticality.

W4-3

Love the SMB3-style bonus room with the first Star Coin! Throughout almost the entire course, you're being chased by Cheep-Chomp, makes me want to softlock the game.
One thing can be improved: the Deep-Cheeps are a bit underused.

W4-Tower

Fun tower level, not much else to say.

W4-A

What's a desert level doing in a snow world?
Anyhow, spike balls and seesaws are a perfect combo. Have been since Sonic 1's Star Light Zone. Nice puzzles you can't softlock, because Spike Balls always respawn.

W4-4

A fun little course, about the size of a vanilla NSMB course.

W4-Ghost

The second room doesn't have a backup if you kill the Broozer next to the ?-Switch. Could you make the door between the first and second room two-way?

W1-Cannon

Haa, a speedrun of my favourite W4 course!

W4-5

W4's That One Level.

W4-6

One hell of a fun course to speedrun!

W4-Castle

The introduction of Climbing Koopas. And Amps. So time for my Obligatory Electric Shock. Why? See you next post. Character limit reached.

Time to complete my story about why I shock myself at least once every run of a Mario game that has a distinct electric shock animation: it all started when I speedran SM64DS. During runs of BitDW, I would run into Amps very often, and this is what caused the "Obligatory Electric Shock" to be a running gag in my runs. And you're welcome,  Arceus, glad you appreciate my feedback.

Okay, time to review World 5.

W5-1

With the Blue Shell, you can clear this course without lowering any drawbridges except the last one (because the drawbridges are considered slopes, so you can Shell Dash up them), and with the Mini Mushroom you can skip lowering all of them! Let's just say this course tickled my speedrunner bone. Also, nice NSMB2 throwback.

W5-2

The stretching/shrinking shroom just past the checkpoint keeps getting me lol!

If you enter the view with the normal exit via the vine, you can climb down into the pit and die. Also, the soundset for the stretching/shrinking shrooms is not configured for the starting area.

W5-A

You put the unused Brick Blockhoppers to good use, blending them in with the environment.

W5-Tower

The elevator is too slow for this kind of levels. If you're to update this hack someday, it might be a good idea to increase the elevator's speed with a code hack.

W5-3

Using the Snake Blocks like the collapsing bridge in Whomp's Fortress, and even have them eat away the ground. In SMW too, Snake Blocks eat away tiles they pass over, so the SMW hacking scene calls them creating/eating blocks. I love how well-hidden Star Coin 3 is.

W5-B

A simple level in terms of design. And that's okay: not every level needs gimmicks, as long as the design is good.

W5-C

The Fire Bro. near the start is near-impossible to pass as Mini, which is bad in a course that encourages being Mini.

W5-Ghost

The way you start really feels as if you've awakened from a grave.
The secret exit is easier to find than the normal one, but in a ghost level, that's OK, because things are never what they seem in these. For the secret exit, you need to bounce off a Scuttlebug to reach a higher-up platform. Sounds familiar?

One point of advice: when you hit the power-up block at the start from the right, the power-up gets flung to the left and may fall offscreen, so I suggest placing some solid blocks out of view.

W5-4

Kind of like the Beat Blocks from SM3DL. Can the Tile Gods be synced to the beat of the overworld theme? That would make it easier to time your jumps.

W5-Castle

You used the Spike Balls both as puzzle element and as obstacle. Placing them on top of moving castle blocks also makes for a refreshing, makeshift new obstacle.

W5-Cannon

A speedrun of W5-3. With how the normal green blocks are placed as two mirrored staircases around a pit near the end, is that a SMB W1-1 reference?

I've found a funny glitch BTW, an upwarp not unlike the infamous TTC upwarp. I might post a video of it on my YouTube if I figure out how to use TwilightMenu++ saves in DeSmuME, because it's in W7 and I'm not gonna play the entire game again ON EMULATOR (I suck at playing on emulator) just for a glitch video.