Can someone please tell me how to reply correctly? Am I supposed to begin with the, reply tab or the quote tab because I've tried both and I'm not doing something right.

I just played it some on my lunch break.  Turns out I am terrible at wall riding the Thwomps.  I did collect one of the big coins and got to the 2nd room, but only by stacking the crates and POW blocks alongside the left ledge to get up there without actually using the Thwomps.

Yeah, I realized I could offscreen the Thwomp without breaking any of the crates by going straight back into the clear pipe right after triggering the Thwomp.  That left enough crates and POW blocks to build a platform up the wall and a safe ledge to land on over the Spike blocks.  From there I was able to do a Long Jump to the big coin and pipe to the next room.

I also played the jump around course and Improbable Mission again to refresh my memory on why those stumped me.  I'm as bad at bouncing on Piranha Creepers as I am at Thwomp riding, lol.  As for Improbable Mission, I can get by the first set of obstacles to the Hammer Bros, but that's as far as I have been.  I'll take some small comfort in the fact that of the 3 courses I haven't been able to complete, there is only 1 combined clear on them.  You have a knack for designing tough courses!

I'm all about the kaizo. I love the quick react feel. That's the next best thing to gameplay besides official Nintendo level design, to me. Thwomerang is my only official kaizo level uploaded but I have quite a few in the stash. 

So, if you want to give it another shot, to prime yourself for the level, you need to spin jump off of the first thwomp just as it reaches the wall, then hard press jump onto the opposite thomp immediately after prompting it to move. From there, immediately jump to hit the coin boxes, allow Mario to slide down and repeat jumping. The next room is the same concept just faster and requires the player to jump on top of the thwomps immediately after one wall ride, to reach the top pipe. If you can get there, the rest is a challenge but it's all the same concept. Thanks for playing. Sorry I didn't play yours but I most certainly will.

Thanks for the tips.  Yes, I will definitely try it again.

One down. Blackjack stumped me. I'd have to keep notes for that one. I'll go thru them. If you wanna tell me the kaizo levels or one that's exceptional to you, lmk. I wanna break records. I have a few records on most popular levels, now. I think the only tech that I can't do skillfully are midairs. I have executed a number of them but never in game, just practice so anything you have that's going to hone my skills send em my way.

Yes, I saw that you set the World Record on my Great Hall of Bowser 30 sec SR.  Nice work.  That one seemed to give quite a few trouble although the timer on it is not at all tight.  I had to set it at 30 seconds since I think the optimal time (as your record reflects) is just over 20 seconds, and you can't set the timer anywhere between 20 and 30 seconds.

Of my other courses, many of them are themed or retro inspired courses or recreations.  Even some of the ones with very low clear rates are honestly not that challenging.  If you're looking for the ones that are less on the easy side, and some that have technical/precision elements to them (not sure if you might have played some of these a while back by the way):

Infiltration of Hangar 66 - Course ID:  W8N-PML-MFG

Downland (TRS-80 CoCo2) - Course ID:  YDQ-723-X5G

Rise of Skywalker - Course ID:  GCT-HQ4-7FG  *the lower path of the broken bridge is the more challenging route

Grand Theft Auto:  Koopa City - Course ID:  GCH-VQ4-14G *this course can be easily beaten by just collecting the overworld coins or taking the ramp near the flagpole.  The more challenging routes are through the Bank or the Hammer Bros warehouse.

TMNT NES Dam Level Redux - Course ID:  0ML-J89-QRF *someone just recently improved on the world record which had been held on this course for over a year

GI*Joe:  Escape from The Pit - Course ID:  RXP-VBP-63G *there is a lift near the beginning of the 3rd level that bypasses the most heavily enemy infiltrated level of the Pit.

The Great Hall of Bowser - Course ID:  8KV-KGW-JPG *This course is what I later used as the theme for the speedrun that you set the world record on.  There's a hidden lower path in the sub-chamber, but this is a safety valve for less experienced players.  The upper path is the more technical and challenging route.

Mega Man Returns - Course ID: TT2-WHN-PVF

Action 19 - Course ID: 1Y7-7FP-DLF *This course currently has an over 9 minute World Record on it, thanks to it comprising of 18 separate games with 9 red key coins distributed amongst them necessary to create the key that accesses the 19th and final game.

7 Labors of Hercules - Course ID: L0M-X25-GWG  *This course was a re-upload after I removed an exploit from it that allowed the course to be beaten in under a minute.  The patched version has only 2 clears so far with the World Record being over 17 minutes.  The 2nd person to clear it told me it took them an hour.  

I was playing and clearing some super expert courses this weekend.  I can also send you recommendations of challenging courses and creators I have come across.

edit - I meant to say Expert courses.  I have cleared a Super Expert Course before, but it was Expert Courses that I was playing and completing this weekend.

New course uploaded over the weekend and updated to OP.  This is another retro inspired recreation.  This time, I attempted to recreate the classic arcade and early console game, "Frogger".  Just like in my Pac-Man Arcade Deluxe course, I again used the Super Mario World underwater theme and Frog Suit.  This aids both with vertical screen navigation, and also stays on theme with crossing the river and playing as "Frogger".  I used semisolids to represent the highway and riverbank.  I placed enemies on tracks that run back and forth across the highway.  After the riverbank, there are more tracks with both "logs" and more enemies running back and forth.  The biggest alteration is that Frogger does not get harmed by touching the water when not on the logs (because the whole level is water!).  So, in addition to the obstacles moving back and forth, I also put scatter some spike traps in the river.  There are 5 homebays.  4 of the homebays have red key coins in them, as well as new Frog Suit in case you took damage along the way.  These homebays have a One Way Wall across them to keep the Frog Suit from floating into the river.  One of the homebays also has a locked door in it, so save that for last.  The locked door takes you back to the start where an On/Off Block is now accessible.  This opens the previously blocked pipe in the center homebay that leads to the You Win screen at the end of the course.  As far as recreations go, I'm very satisfied with how this one turned out, and it has gotten some nice feedback already. 

Frogger

Course ID: 9JL-BLK-XKF

Description:  Guide 5 Froggers across a busy highway to reach the riverbank.  From the river, cross floating logs while avoiding hazards to safely reach the homebays.

Likes: 10

Played By: 18

Clears: 11

Attempts: 36

Clear Rate: 30.55%

First Clear:  Luigi05

World Record: 0:21.001 (Se7h)

Uploaded: 1/9/2021

This just happened over the weekend.  "Mario Maker Kart Quadruple Dash" crossed the 1,000 players mark.  So, I'm already working on a deluxe version of the course to commemorate the achievement.