Note: This game is also known as: Super Smash Brothers Melee

In world 4-2 you start out by a big POW block. You must wait for the right moment to pick it up and throw which results in a 1up. Continue to the right and go up the vine. Get off the vine and go to the left and do a super jump (hold the down button till your character flashes and press A) to grab the heart. go down the vine and jump off go to your left and grab the POW block and throw it to get a 1up. Continue to do this by going up the vine (grab heart if necessary) and coming back down and throwing the POW block. You may get up to 99 lives
Sent in by: Toxity

Get Yashi:
Sent in by: Sylvarus
Once you have collected all of the Yoshi eggs, yoshi will become a playable character in Super Mario Bros. 2.

Get sonic and tails on super smash brothers melee: To get sonic and tails beat 20 guys on cruel melee.
Sent in by Sk8brdr3493

New Mode/Level select: 
Once you have beaten Wart and after the credits the title screen should have changed and a yoshi egg should appear. After you select a player there will be a level select screen and you will be able to collect yoshi eggs in the dark world. 
Sent in by Taproot2006@aol.com

Cheat code:
World 6-3: Immediately after entering the level don't go right. Allow yourself to almost sink out of site in the quicksand to the left of the entrance. Begin moving left and rapidly press the A button to walk UNDER the wall and find the door to the pyramid area there. 
Sent in by: Benjamin Quatier - age 10.

Cheat code: 
In any level, pick up a giant enemy (Shy Guy, Ninji, ect) and throw it. A heart will appear. You may use this as many times as you like on the same enemy. You can also get a heart if you kill 3 or more enemies with one attack.
Sent in by: BoB

Hints: 
To get lots of one ups beat the game then go to level 7-1 and go to the place to get the end of the level were you see this mushroom rock pick it up and put it one space away from it then when the shy guys come out of the pot they will get caught and when they stop coming out of the pot go grab one and throw it at them and you will either get 1 1up or 2 1ups or 3 1ups. 
Sent in by: Carl Malone 35

Free Hearts  -  If you're ever in need of hearts, look for one of those giant Shy-Guy enemies. Jump on it, pick it up, then throw 
it on the ground again. A heart will come out for you to collect. You can do this an infinite number of times to the same giant Shy-Guy, too. 

Gain an extra life in each level  -  To gain an extra life in any level, collect all 5 Red Coins scattered throughout each level. 

In-game reset:-  Press Select + Start + A + B during game play.

Suspend game:-  Press Select + R during game play to suspend the game without turning it off. Press Select + L to resume.

Deleted saved game:-  Hold L + R + Select + Start + A + B and power on the system. Keep the buttons held until you are prompted to delete the existing game. 

Yoshi mode:-  Successfully complete the entire game of Super Mario Brothers 2 to unlock Yoshi mode You do not need all the red coins. In Yoshi mode, you must find two Yoshi eggs hidden behind the potion doors. There are two eggs for each stage.

Warp To Level 6 - In the begining of level 4-2 jump down onto the whale and go to the left. You will find some red grass patches which will have a potion. Carry the potion through the entire stage, and rather than go through the door, you can jump on the last whales tail and jump over a small gap to find a vase. Now drop the potion, enter the door and go down the vase.

Warp to World 4-1 - In world 1-3 after you get the magic bottle/potion go all the way to the right until you reach the vase thing. Use the magic bottle/potion, jump on the vase and go down. Instead of not being able to go down you'll now be warped to world 4-1.

Warp to world 5 - Go to level 3-1. Go to the waterfall and go down. Keep going until you reach the hill, go in the door on the hill. Pull up veggies until you get a potion. Go to the right and place the potion next to the pot. Enter subspace and go into the pot. You will be warped to the 5th world.

Warp to world 7-1 - Go to world 5-3 as Luigi. After you climb the first ladder, power jump (hold down until you are glowing) on to the platform you normally can't reach. Pull up the plant on the right side of the warp pot. Throw down the bottle and go through the door. In the dark world, jump on top of the pot and go down. You should see the screen wiggle and it will say warp world 7 on a screen with Birdo.

Yoshi Challenge & Finding Yoshi Eggs - After defeating Wart in World 7-2, you unlock a special Yoshi Challenge game on that file. It allows you to replay any stage in search of two Yoshi Eggs. Unfortunately, it gives no description of the kinds of areas the eggs could be hidden. The eggs are hidden in Subspace, but the searching for the egg is the challenge. Also, if you lose a life, you lose all of your eggs as well.

Yoshi on title screen - To get Yoshi on the title screen,beat the game on Yoshi's challenge and instead of an egg,there will be a Yoshi.
Sent in by Earl

99 Lives - Go to World 3-3. Climb the ladder then jump over the spark enemies to the door over on the ledge. Find the red grass patches; the last one is a shell. Pick it up. Go back to the bottom of the area, and then toss the shell into the doorway. Stand on the ledge and wait. After the shell defeats enough Shy Guys to earn 1,600 points, you'll start earning extra lives. You can easily, and quickly, earn up to 99 lives.

Bald Birdo - When you get to the green Birdos jump on her head and press B to pick her bow up. Birdo will be bald!!! If you throw the bow back at Birdo it will land back on her head.

Clear all saved data - To clear all saved data, including high scores, SMB2 save slots, and unlocked secrets, just press: L + R + A + B + Start + Select, while switching the system on. A prompt will show up, select Yes to erase all saved data.

Decorative Mario Heads
For every 2 million points you get in Super Mario 2 game, you get a little Mario head next to the High Score! The maximum is 10,000,000 points / 5 heads. Any more points will NOT get more heads.

Free Hearts - If you're ever in need of hearts, look for one of those giant Shy-Guy enemies. Jump on it, pick it up, then throw it on the ground again. A heart will come out for you to collect. You can do this an infinite number of times to the same giant Shy-Guy, too.

Gain an extra life in each level - To gain an extra life in any level, collect all 5 Red Coins scattered throughout each level.

Quick Reset - Enter the following code at any time during the game: A + B + Start + Select

Then the game should reset to the Title Screen

Sleep Mode - Any time you need to pause for a long time,but don't want to waste battery, any time in the game press simultaneously

SELECT+R - This will shut off your LCD screen and sound, and waste minimal battery. To return to the exact spot you were just in on your game press

SELECT+L  - simultaneously. The select+r may be hard if your game is paused and you try to activate sleep mode.

Action Replay Codes

(M)
9f5c79e3
292e8a5b
1802dcf0
525fe061

Inf Lives
8c706ce2
7289b36d

Max Hearts
42d8dcb7
16e09d2c

Inf Star Power
831814ac
06354ae1

Always Big Mario
adf2a0ee
94504fb2

Always Power Jump
d633983a
476cc5f5

Infinite Float
28d79342
8b546cf3

Have All 5 Coins
7961aed6
dae39f98

Max Score
0e1ce091
424397dc

Max Score P1 Classic
4cb2957d
8be9492f

Inf Lives Classic
a47b5f6f
38caf74f

Start On 1-2
d016c98f
e7b80a66

Start On 1-3
b0973511
bd18403b

Start On 2-1
783d2499
2789e78f

Start On 2-2
4f8cb2b3
dfff0e53

Start On 2-3
4be13681
b84c3c24

Start On 3-1
697a1700
dd9a6de0

Start On 3-2
ffe2291d
cd210983

Start On 3-3
2c047ec2
c15ce453

Start On 4-1
344d7dbc
77a72868

Start On 4-2
f0de95a8
df36cfc5

Start On 4-3
db0d21d5
1cf8602a

Start On 5-1
bee06b2e
a1bcd8d6

Start On 5-2
c0f438cb
1cfdb481

Start On 5-3
add62140
d20f357b

Start On 6-1
8a0996a6
b02dbf1d

Start On 6-2
8466a731
3177ae04

Start On 6-3
ce10190d
be694c61

Start On 7-1
1af191dc
548fb12c

Start On 7-2
1af191dc
548fb12c