Since you have given me a lot of construtive criticism and suggestions for my hack, I feel that I should try to return the favour. So here's some things I noticed in the first video:
-The sprite shown when you hit a turn block looks slightly different from the block itself.
-The "right" sound used for the gun is kind of weird...
-The blue/yellow things (I have absolutely no idea what they are) look kind of bad with their current palette.
-If the blue circles are midway points, you might want to make them play the midway point sound when collected, to avoid any confusion.
-The coin created when you shoot an enemy has a wierd black patch in it...
-Mask Koopas turning into Waddle Doos when stomped doesn't make much sense... And besides, they turn back into squished Shelless Koopas when stomped.
-Speaking of the Mask Koopas, since they aren't Koopas at all but rather Waddle Doos, the second message block ("Considering all of the Koopas...") doesn't make much sense either.
-At the end of the level, Mario is walking into the wall. You might want to extend the ledge he's on... And what's up with the post-goal Bullet Bills?
Except for the invisible custom blocks, I didn't find anything bad about the level in the second video, apart from the On/Off Block's bounce frame being glitched. Since it seems to be using an unused tile, this shouldn't be hard to fix.
Apart from these minor issues, the levels seems really good. Keep it up!
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