In world 5-3 come up to the surface and throw the shell on the ground there, it will keep bouncing off of the walls back and forth. Jump and land on the shell and wait for the birds to drop the bombs. The shell will kill the bombs, and after you get a certain amount you start getting 1-UPS, you can do this forever until you have 99.
Instant Reset
To trigger the game's built-in soft reset and restart the game without using the power switch, simply hit the following buttons at the same time: Select + Start + A + B.
Level Warps
Warp to World 4: In level 1-3 go to the area just before the brick background. Pick up the plants until you get a bottle. Then go past the brick background until you find a pot and throw the bottle on it. Go through the door and down the pot into World 4.
Warp to World 5
To warp to level 5, first get to level 3-1. When you enter the first door, fall all the way down. You have to be in the middle as you fall. When you stop, you will find a platform with a door. Enter the door, then look for the potion in the grass. Pick it up, then throw it on the ground, enter the door in cyberspace, and go into the vase and you will be at level 5.
Warp to World 6
In level 4-2 In the area with the whales find a bottle and throw it on the next pot. Enter the doorway and go down the pot into World 6.
Warp to World 7
Work your way to level 5-3. (It would be a good idea to choose Luigi for this level because of his superb jumping skills.) Go up the ladder at the beginning of the level, and then jump up onto the ledge above the ladder. As soon as you get on top of the ledge, grab the first grass on the right. It is a potion. Use the potion and go through the door. Now, while in sub-space, go down through the jar and voila! Now you're in Level 7.
Suspend Game
While playing a game, press Select + R to suspend the game without turning it off. Press Select + L to resume.
As many lives as you wish for
When in level 1-1, when you go in the door on the ground towardsthe end, you will see a little creature and two roots. Dispose of all of them by throwing them at the 1-up bubble. Get the extra man (not necesary to get as many lives as you want). Next climb up the vine, pick up the last root (closest to the the creatures), wait for the one closest to you to land on the ground, then throw the radish at it. When it hits the last creature, you will get 1-up! Go back down the vine then climb back up and do it over and over again!
99 Lives on Level 5-3 (alternate)
(This may seem like a lot of work for 99 guys, but if you are playing the game and have to complete the level anyway, why not refill your men)
While going though level 5-3...(this is when you've already accended the ladder from the start of the level, walked past all the birds dropping bombs, decended the second ladder to go back underground, walked to the left to the Tree with the door and gone through). When you decend inside the tree, then make your way up back to the top...you'll be approached by a walking fire plant. Right near (actually before he comes) there will be a pot vase that you can go inside. Once inside, you will land on a 4 shy guy ferris wheel...just on top of one of the shy guys. Pick him up, then as you ride around, just as you get to about the 9 o'clock position, throw the shy guy to the right, he should take out 2 guys at a time...even if you just get one, you get a 1 up per hit. Then as you hit the top of the "ride", jump up to exit the pot, then go right back down to be in the same position, to do it all over again.
Now what's good about this is, there's no way to loose a heart or get killed this way, plus, after you master how to throw the shy guys, you'll only have to do it a real fast bunch of times to get 99 lives. Like I said, it's not the fastest method to go and get 99 lives, but if you have to clear that level anyway, it's definently a spot to visit on that level, for a non-threatening 99 guys.
Select Yoshi as a Playable Character
To select Yoshi as a playable character you must succesfully collect all 40 Yoshi eggs in the Yoshi challenge mode.To see that it has been unlocked Yoshi will hatch from his egg on the title screen.
Yoshi Challenge Mode
To get the Yoshi Challenge mode you must succesfully beat Super Mario Bros. 2. After you have defeated the last boss you will unlock the Yoshi Challenge. To know that you have unlocked it there will be a Yoshi egg at the title screen.
World 7-1: Find Green Yoshi Egg
From start, climb up the ladder. Walk right to a pillar with a single plant on it, and lift it up for a potion. Throw the potion to the left before the Bob-ombs destroy the walkway, then enter Subspace to find the Green Yoshi Egg.
World 7-1: Find Red Yoshi Egg
Make your way to the area with tall ladders that lead to the boss door. Climb up and you'll see two pillars on either side of the screen. Pull the plant on the right pillar to get a potion, then jump across to the cloud that supports the left pillar. Drop the potion and enter Subspace to find the Red Yoshi Egg.
World 7-2: Find Blue Yoshi Egg
From start, go right and enter the castle. Run all the way to the right and climb the chain, then walk left and climb the next chain. Go up and look for a door on the left side of the screen. Next, go down through another door. Pull the plant on the right to get a potion, then drop it to enter Subspace and find the Blue Yoshi Egg.
World 7-2: Find Light-Blue Yoshi Egg
From start, go right and enter the castle. Walk right and shimmy down the first chain, which allows you to go downward. Continue down through the Mushroom Blocks and enter the door at the bottom. Walk right, go through the door, then walk left and grab the potion. Walk back to the right, and throw the potion near the upper-right pillar. Enter Subspace to grab the Light-Blue Yoshi Egg.
Bald Birdo Trick
Start on any level and pick your character as Toad, complete the level, then when you face Birdo ( the dinosaur that spits eggs at you! .) As soon as she has fired an egg at you jump on her head and you can pull her bow off!. Now Birdo will be bald!
Note: This code is not a cheat it is just for fun.
Play as Bowser
First, go to the Map Screen. Press R, R, L, L, B, B, A, A, Select, Select, B. Note: Do this fast. If you did it correctly, you should hear Mario say "Mamma-mia! It's Bowser!" Then, turn off the Game Boy Advance. Turn it on, then when you go to the map screen, you will see Bowser dancing on the level you are on. Press Select to become a Bowser with a blue shell and B to go to the normal red shelled Bowser.
Link's Awakening Cameo
The final boss Wart, is the EXACT same character from "The Legend of Zelda: Link's Awakening". This guy is the frog who gives you the "Frog's Song of the Soul". (You can find his lair after you complete the "Signpost Maze")