Instructions
Quickest Method to the Final Level
Play through level 1.3 until you see a white block towards the end of the level. Stand on the block and press down for five seconds. This will cause you to fall into the background. Run to the right behind this black background and you'll reach a house with the first Whistle inside.
Get to the end of the first area with the Dry Bones in the World One fortress. Get a running start with Raccoon Mario to fly above the wall with a question block. Go right as far as you can, then press "Up" to discover a room with the second Whistle in it.
Go to the upper right corner of the map in World Two and use the Hammer to break the dunes. Go into the new portion of the map that is uncovered after using your Hammer. Defeat the Fire Bros. in this room to find the third Whistle.
Use a Whistle to get to the first Warp room. This room will have a row of tubes you can use to skip to either World Two, Three or Four. Go into the pipe for World Four.
Use another Whistle to get to the Warp room for World Five, Six and Seven. Go into the pipe for World Seven. Use your final Whistle to get to the last Warp room and go into the pipe for World Eight. This is the final level where you need to defeat Bowser to save Princess Peach.
Other Quick Paths Through Levels
Play through level 1.2 until you see some platforms going up. Jump onto the bricks next to the platform. Jump onto the other platforms and ride them to the top. Jump onto the next line of bricks and run down it to get to a "Warp" room where you can select World Two, Three or Four.
Grab the Raccoon Suit in level 2.4 and get your "P" all the way up. Fly up to the upper left corner of the screen. Smash the brick that you see there and the bricks above it to access a hidden area. Continue until you get to the bricks over the water. Smash the bricks on the right until you uncover a "P" block. Jump on the last music note before you use the "P" button to change the bricks to coins so that you can drift down to the ground and the end of the level.
Begin level 5.1 and get your "P" meter all the way up. Fly up to the pipe and enter it. Go to the bottom of a maze after exiting the pipe. Duck down and then fly up to the narrow paths of a maze. Continue ducking down until you are through all the straits. The level will be over after you come out of this path.