Ready to slap yourself for not figuring it all out before?
At start, run right till you see a bird in a cage. Talk to it, take it with you, and proceed right.
(It's worth noting at this point that you can choose whatever answer you like to the folks you speak to. It never matters, they're just different conversations.)
You'll find a fisherman, who states that a pipe is blocked. Time to get it flowing.
Jump over the pole in the next screen by way of the provided platforms. Run right some more. At the second screen, you come across what seems to be a decaying peach, remember this, there's a test on it tomorrow. Talk to whomever you come across (by getting near them).
If you're running to the right (and who isn't?), you'll come to an arch with a hole in it next to a rock column. The arch is old-school 3-D, which just means you can only stand on the middle of it. Jump on top of it and over the column. Run right.
After a few screens, you come to a hill with a hole at the bottom (looks kinda like a face). Fall through the hole and talk to... well...whatever it is, then run LEFT (hooray for left!) back to the fisherman.
Grab the hook he lowers and go back to the whatever-it-was-that-you-talked-to-stuck-in-the-pipe and pop it. Run right.
Jump outta the hole in the top of the pipe. Jump into the large chasm, which leads to the Silver Shute. Follow the only path (A LEFTY!!!!) to it's end, through the Beetlejuiceian worm's mouth. Jump into the hole above you.
Congratulations, you're worm poo, and so is the light(?). Grab it and run right.
Once you get back to where you fell in the Silver Shute, climb up to the small ledge above the pipe's end. Jump to the rope and swing across. Jump over the tree, or bounce off the fruit in it's branches.
Directional control changes to it's opposite after a few screens. Don't panic, it's easy after a few seconds. Jump across the hangman's see-saws to get through.
Memorize the song's note's, you'll need it. Run right
Trampoline time! Just jump on and wait till you reach the third screen up. Jump left towards the flowers when you get there, and run left till you can talk to someone.
Go back from whence you came, and re-enter the Silver Shute, exiting again as poo.
Run right to the swinging kid, talk and gain a super jump power.
Run back to the left all the way to the pier. Jump on it and run left till you hit the piano.
Play the song (did you remember??) and enter the glowing hole.
There's three switches here, find em (some up, some down, all dark.) and press em (doin it right? did it click?). Enter the next glowing hole
Three more switches spread across a few screens here. Find em (some up, some down, all dark.) and press em, then fall down the hole they open up.
Hey look! A Doorbell(?)! Ring it fool! If for whatever reason you can't seem to reach it, bounce off the fruit on the ships mast directly below it.
Thee 'nd
One final note: Personal preference, but I find holding the jump button constantly while holding left or right seems to speed up travel somewhat. Maybe it's just me, or maybe it just helps pass the time.