"Generic"?! This looks amazing! Tob, you should also post your videos so we can see how they play out. My only complaint is the weird looking hills in the title screen. Maybe make them more round and have further spaced eyes? Besides that, it looks good so far, and I like your thread orginization.
Just can say this is still a very good one, the only thing that bothers me is, that the levels are sometimes a bit repetitive, meaning, a feature is sometimes too often in the levels, just a bit changed.
If you improve that a bit, this hack will be insane.
The original level was fine imo (even if a bit too hard due to a few annoying jumps), but this one looks fairly interesting as well! The sticky block gimmick is definitely interesting, and you made a great use of it overall.
Just a nitpick, but I think the darkness effect might be a bit too obscuring right now, maybe it could use some tweaking? It might be better in-game, though. Also I don't remember seeing these stars in the demo, curious about what they do.
In terms of visuals, it looks pretty great. It clearly shows you've taken care compiling your visuals, palettes, and gradients, and it offers a vibrant look. I would recommend changing the background in the forest stage to use its own dedicated image rather than recycled foreground graphics, though.
In terms of level design, I think the demo falls a bit short. Most of the difficulty seems to come from low ceilings. In general, I would advise against low ceilings in most any setting and instead rely on other techniques to achieve your desired (high) difficulty level. Platformers like Mario are best enjoyed when you can exercise a high degree of movement freedom. In addition, having ceilings in non-cave levels tends to feel a bit unnatural and forced. In your demo, this point is further strengthened by the fact you give out plenty of Raccoon Feathers, but present barely any opportunity to use them.
The overworld is very colorful and well made.
The demo is fairly short. I played without savestates and got around 15-20 minutes of gameplay out of it. Less experienced players will probably take a bit longer due to the difficulty, which seems to be on the tough side.
I did notice a few technical problems, but since I played on ZSNES I'm not sure if they also occur on more accurate emulators. In some stages (at least the forest and the cave) the music tends to spaz out on a few notes. The HDMA gradients seems to carry over into loading screens and fadeouts, which looks weird. Bronto Burt animation does not freeze when all other animations do, which is a very minor thing but something you might want to look into for the sake of consistency anyway.
I did really like what you have on show here, and I look forward to future updates!