Super Mario Bros Secrets
Unlimited 1-Ups
Get to world 3-1, and become Super Mario. At the end of the level(the staircase before the end flag) you will see two turtles coming down the stairs, jump over the first one and then jump on the second one. It should hit the stair and bounce back, from here jump on it and keep yourself up, after a certain number of bounces without hitting the ground, each consecutive bounce will get you a 1-up. Get as many as you want but be warned, if you get over 100 you will get a Game Over.
Continue
If you run out of lives and want to continue then at the game over screen press and hold A then press start at 1 player (or 2 player) and you will start at the beginning of the world at which you died!
Level Warp
To warp to Worlds 2, 3,or 4 during World 1-2, go to the end where the 2 platforms are rising, get on the first platform, and use it to jump onto the highest structure in the middle, then jump on the next rising platform, but this time, when it reaches the top, jump onto the TOP of the level. Walk foward and drop down the small jump, and you can now warp to Worlds 2, 3, or 4 by going down the desired tube, and pressing down.
Level Warp to World 6,7 or 8
To warp to World 6,7 or 8 during World 4-2, go to the place where three blocks are can be seen (where a pipe can also be seen). Jump below the third block where you can reveal a secret block but be careful on jumping below the 1st block because you can’t break it thus going to the secret warp world unless you are a small Mario. Then step on to it and break the 2nd and the 3rd block. After you have done this, go down, then jump again below the second block now (it should have been broken now). The position of the two revealed blocks must be a stair from right to left. Anyway, step on to the 2nd block then braek the 1st block and there you can see the vine going up. Climb until you reach the day light again. Get some coins if you wish and you can now see three pipes like in the secret warp Worlds 2,3 and 4. Go down your desired pipe.
The Fireworks Secret
This is a pretty commonly known secret. If you touch the flagpole of any level with either 1, 3, or 6 seconds left on the ones place of the timer, you will get that amount of fireworks. For example, if you touch the flagpole with 126 seconds left on the time, you will get six fireworks!