Onto a few things. On World 1, when you hit the vine block, climb to the "!" and warp to the cloud level, I found a small glitch after you come out of the pipe back on the main level, you can move Mario slightly to the right a little bit at a time and the screen will scroll backwards a just enough for Mario to hit the vine block again. Now normally this wouldnt be a big deal, but since a 1 up is possible every time one warps to the cloud level, a player could easily exploit this for 100 lives. I personally dont know what would fix this, but I would like to see if you could fix it somehow.
Last thing, and this is just me personally, I feel like the stages are lacking a few powerup blocks. I believe you are shooting for an arcade feel, but even then, I feel like a powerup should be somewhere near the middle. I might have missed them, but I tried to get every block I seen on each level. Other than that, I think this hack is rocking.
I am wanting to play through the entire game this weekend and maybe see if I can find any glitches or bugs and hopefully beat it.