Guess what? When the cannons fire cannonballs at you, you can eat the cannonballs!

After you have gone over all the hills there is a pipe that ‘Shy Guys’ come out of. Ignore them and go past the pipe and get rid of the Killer Plants in the next two pipes to the right (one above and on the ground). A Kooper is walking between the two pipes on the ground. Jump on the Kooper and send his shell spinning between the two pipes. ‘Shy Guys’ continue to jump out of the pipe on the left and every time the Kooper shell hits them you will hear a different sound that means you’re getting lives! Stand on the pipe on the right and the lives will continue for as long as you stay on this screen.
I have tested the method and it really does work. this is really going to help me on bosses and world 6.
while the shell hits them you see the one up happen over and over.

In the game there is a coin with one of the baby's faces on it in each level and if you manage to find all of the coins in each world you unlock the harder version of a minigame in the minigames menu!
Bouncy Maze (Hard) - Get all character coins in World 3
Egg Toss (Hard) - Get all character coins in World 5
Flutter Challenge (Hard) - Get all character coins in World 2
Speed Eating (Hard) - Get all character coins in World 4
Tulip Shooter (Hard) - Get all character coins in World 1

Have you seen a rotating arrow? Well, did you know you can EAT it? It will reappear! It doesn't do anything, but strange that you can eat it.

If you get a 100 points on all levels in a world, you unlock a bonus level. This level will allow you to get extra items and level ups!

Do a flutter jump will with some eggs. Press X to aim your egg, but Yoshi's feet will stay still! They should be moving, shoudn't they? He can't flutter without moving them... hmmm?

when in a underground or poorly lit area their should be a lamp on the wall. if you eat it (y) yoshi will have 3 blasts of flame breath!

Get 700+ points on any world to get a bonus game. There are 5 to get.

Time Attack: Beat the game.
1st secret level on every world: Beat the game.
2nd secret level on every world: Get 800+ points on that world.

To restart your game, what i mean is to restart the level thing, press R, L, START, and SELECT at the same time.

If you beat the game, you unlock 'Time Trail' mode, and there is 5 levels to play, one from each world. You will play with black yoshi!

First get DK. Sallow a enemy, then go up a vine. You should 'look' like you have a enemy, but you don't! Climb down and you won't have a enemy in your mouth!

At the end of each level there is a ring that can have 0 to 5 flowers on it depending on how many flowers you found in the level. When you jump in this ring there will be an imaginary ball that circles around the ring and if it stopped on a flower you would get warped to a bonus stage. There is another way to get one of these 5 bonus levels however and here's how...
Flip Cards - Get a total of 700 points in World 1
Match Cards - Get a total of 700 points in World 3
Roulette - Get a total of 700 points in World 4
Scratch and Match - Get a total of 700 points in World 2
Slot Machine - Get a total of 700 points in World 5

Once you've beaten the game, you will be rewarded the Time Trial mode. To access Time Trial enter the File Menu like you would starting up a game. Your completed game file will have a star icon and will have the word 'Clear!' under where the world should be. Click on your file and you will notice 'Time Trial' on the bottom right corner where a question mark used to be. In Time Trial mode, you will be rewarded 5 extra levels, one for each world. You will also be able to play those levels with a black Yoshi.