Okay, so I'm really late to the party... But man, that music in Mario DX is seriously screwed, especially the bit at 5:30, euck. It just sustains a note that sounds like an old cumpter dying. It's a shame, the actual tune itself doesnt seem too bad if it wasn't butchered up so badly.
As far as gameplay, there's not much to say besides that it looks pretty awful to control. Mario's physics are so crucial, and it's what pirates always get wrong... Super Mario World NES with the yusuplaz game genie code is the only thing even close to 'acceptable' i've seen so far.