The walkthrough is below. Highlight the invisible text beneath each heading for the specific directions. In the Midgame section, actions don't necessarily have to be done in this order; this is just one of the shorter paths.
Introduction: Falling Down the Pit: * Z. Z. Z. Z. Z. Escaping Orchestra Pit * (from Pit Bottom) CLIMB WALL. ENLARGE HOLE. G. G. G. E. Opening the Trapdoor * (from Narrow Passage) GET ROCK. N. PUT ROCK ON PLATFORM. S. W. GET TPT. E. NE. * (from Quarry Entrance) LOOK AT CHUNK. GET NOTE. READ NOTE. OPEN TRAPDOOR. Navigating the Darkness * (from Darkness) PLAY TPT. NE. PLAY TPT. E. PLAY TPT. Z. Z. Z. Z. Midgame: The Black Puzzle Piece * (from Construction Office) GET BOOK. W. GET RUBBER. E. E. SW. GET BLACK PIECE. W. S. * (from East of House) TIE RUBBER TO TREE. PUT PIECE IN SLINGSHOT. FIRE SLINGSHOT. Finney's Device * (from East of House) N. DROP ALL. SW. GET BLACK PIECE. W. U. S. OPEN PIANO. GET WHITE PIECE. * (from Music Salon) N. D. SE. PUT BLACK PIECE IN BLACK SLOT. PUT WHITE PIECE IN WHITE SLOT. GET JIGSAW. Finney's Music * (from Workshop) NW. U. SE. GET HEAVY HEART. LEARN HEAVY HEART. LOOK AT SHELF. GET BOOK. READ BOOK. * (from Study) NW. S. GET JIG. CUT JIG WITH JIGSAW. LEARN JIG. N. D. E. DROP ALL. NE. TAKE ALL. Leonine's Music & Leonine's Key * (from Finney's House) S. S. E. NE. E. LOOK AT RAINY DAY. TAKE RAINY DAY. * Find Leonine, wandering around the Community, ASK LEONINE ABOUT RAINY DAY. PLAY TPT (Jig). GET KEY. * Return to the Magic Lab. TAKE RAINY DAY. LEARN RAINY DAY. Passing Moilan * (from Magic Lab) W. N. N. N. GET CUP. S. PLAY TPT (Rain). PLAY TPT (Rain). PLAY TPT (Rain). W. W. SW. FILL CUP WITH MUD. * (from Quarry Trapdoor) NE. E. E. N. N. GIVE MUD TO MOILAN. OPEN GATE. NW. N. Opening the Bank Safe * (from Bank) PUT MANUAL (or any object) ON PLATFORM. PLAY TPT (Heavy). GET MANUAL. STAND ON PLATFORM. * (from Bank) UNLOCK SAFE WITH COPPER KEY. OPEN SAFE. GET NOTE. Opening Poont's House and Getting the Mirror * (from Bank) S. OPEN DOOR. E. GET EXPERIMENTS BOOK. READ EXPERIMENTS BOOK. N. PLAY TPT (Jig). N. GET MIRROR. S. * (from Poont's Lab) W. SE. S. S. SE. E. E. E. GET IN RECESS. PLAY TPT (Heavy). STAND. W. SE. W. PUT MIRROR IN FRAME. * (from Vault Door) GET COLOUR. LEARN COLOUR. E. NW. W. W. NW. S. S. SW. W. Getting the Herring * (from Fish Pond) PLAY TPT (Colour). PLAY TPT (Duck). Wait for duck to catch the herring. GET HERRING. * (from Fish Pond) E. NE. N. N. N. N. NW. E. Entering Squiggy's Tower * (from Poont's Lab) PUT HERRING IN RECEPTACLE. GET HERRING. W. PUT HERRING IN CLEFT. D. ASK MULLOG ABOUT RING Finding Mullog's Ring * (from Mullog's Lair) E. SE. S. S. E. READ PLAQUE. LOOK UP 113 IN MANUAL. LOOK UP 114 IN MANUAL. Finding the Solution to the Security Maze * (from Outside Courtyard) W. S. SW. GET PAMPHLET. LOOK UP FOU-LLAMA IN TOME. NE. N. E. NE. Navigating the Security Maze * (from F Courtyard) NW. E. NW. N. NE. E. W. N. SEARCH STATUE PARTS. GET GOLD RING. Reading the Butler's Diary * (from Front Yard) E. Wait for the Widow to be engrossed in reading. PUSH FERN. W. W. READ DIARY. LEARN LOVE. * (from Butler's Cottage) E. E. TELL WIDOW ABOUT DIARY. Wait for the Widow to be engrossed in reading. PUSH FERN. Z. Z. * (from Drawing Room) PLAY TPT (Love). W. S. Navigating the Security Maze * (from A Courtyard) E. SE. W. S. W. S. SE. W. SW. * (from Outside Courtyard) W. N. N. NW. D. GIVE RING TO MULLOG. U. (Optional, if you've forgotten to get the ring) Returning to the Fou-llama Estate * Go to the Bear's Den, north of Poont's Lab. S. PLAY TPT (Love). N. MOVE PALLET. D. Getting the Literal Music * (from Tower Top) PLAY TPT (Colour). GET LITERAL. LEARN LITERAL. * (from Tower Top) D. E. SE. S. S. SE. E. E. SE. W. Opening Snoobar's Vault * (from Vault Door) PLAY TPT (Literal). W. GET DOOR. GET MODULATE. LEARN MODULATE. E. NW. W. W. NW. S. S. SW. End Game: The Door to the Surface and the Key * (from Rock Wall) PUT DOOR IN DEPRESSION. NE. N. N. E. E. LOOK AT PRACTICE BOOK. PLAY TPT (Modulate). GET KEY. * (from Opera Hall) W. W. S. S. SW. UNLOCK DOOR WITH SILVER KEY. IN. U. U. U. CLIMB HANGINGS. The Final Showdown * (from Throne Room) PLAY TPT (Heavy). PLAY TPT (Heavy Love or Modulate Jig). PLAY TPT (Colour Rain). PLAY TPT (Heavy Duck)