Let's give feedback based on the screenshots.
That seems fairly good for a first level so far, but the invisible coin blocks are so overused and annoying to deal with, invisible dotted coin blocks are where it's at! In other words, take the dotted switch blocks (the yellow one, to be exact, or any other that you seem to think it looks good) and make it act like tile 21.
there is cutoff on the water because of the wall of cement blocks. Maybe replace the last ones with skinny horizontal pipes and the rest with upside-down ledges? Also, the clappin' chuck gimmick seems overused, unless you're making it so the chuck do something.
I think the ceiling of brown blocks isn't needed, replace them with upside-down ledge. Same with the turn blocks and part of the bullet bill machine. Also, no need to put an 1-up at the beginning of every level, unless you die everytime after hitting the midpoint. Other than that, simple.
For a level called Hot Foot... this doesn't seem to be like it at all, because when I've seen this name, I thought it'd be a cave. There are floating munchers on the last screen, replace them with upside down ones with cement blocks or something above them.
Hmm, not bad at all, though if you bounce on the note-blocks, they may show glitched graphics, but you're using the grinder, so the only option is using the disassembly, which seem to be quite difficult for you.
Other than that, it seems good for a first hack so far.