Wow, this hack is the highest rated hack on the site! Its rated better than SMW2+3!
lol. Are people seriously complaining about the difficulty pre-world 5? It's really not that hard at all until you hit the ice world. Sure, there are a couple of tedious, and/or stupid levels here and there (Firehazard Canopy still comes to mind), but overall, it's pretty run-of-the-mill in terms of difficult.
I'll admit that the ending is still pretty nightmarish though.