After completing the game, go to the Special world 1 and complete the castle. There you unlock Luigi once you finish the castle. After that, tap on the L below the world map during gameplay to become Luigi.
Toward the end of the level, while jumping up the big shaft via the spotted bouncy platforms, use the final bouncy platform and angle your jump to left to reach a narrower shaft. Note: You may need to do some wall jumps. Go up and to the right. Run all the way to the right to reach an orange pipe that will advance you to World 5.
Get a Tanooki leaf and play level 7-1. When the level begins, run towards the flag. When you come to the pit with the water, jump and hover over it. If you do this you can hit the flag and complete the level in 5 seconds or less.
If you save and quit while playing in any of the special worlds, the next time you go to the home screen there will be alternate video. This can be undone by saving and quitting in any of the first 8 worlds.
Find the three Koopa Troopas and three coin blocks just after the checkpoint flag. Step on the first long coin block on the ground, then walk down onto the Koopa Troopa below when it moves directly below the coin block. If timed correctly you can bounce off the Koopa Troopa repeatedly and make infinite lives.
Play W5-2 until you reach the right-most area with spinning spike balls and little areas you can drop down. Drop into the right area and crouch, then walk right to access a new room. Light all four torches with fireballs to hear the familiar tune that normally plays when you solve a puzzle in Zelda.
Play Ghost House (4-4 in the Normal world) until you reach the end, but do not grab the flagpole Instead, stand near the fence in the upper right area. After around 30 seconds a haunting ghostly figure will materialize. It only remains in place for around 15 seconds, then fade again.
It is possible to go over the maximum number of 999 lives and have up to over 1,000 lives. By utilizing the 1-up trick found in 1-2 or anywhere else with a koopa troopa and a wall nearby, this is made simple. Once you reach 1,000 lives, there will be a unique sound effect and some applause, and your hundredth place for your lives will turn into a crown. Same goes for the tens, and the ones; they all turn into crowns once they exceed the number 9. Once you reach the maximum number of lives(which is 1,110), the same sound effect and applause can be heard once more.
Get the Tanooki leaf and play stage 1-Castle. After meeting Bowser, run towards him. When you reach the gap between where you are standing and the bridge he is standing on, jump and float over the gap, using the tanooki leaf, to land where the Bowser-Button are. This makes it very easy to beat him, and gets you a much better time-score.
Jump on top of the coin blocks after the flag pole, then jump further up and away from the screen. You will land on a narrow ledge. Run past this part of the level and, when you reach a gap in the higher area, jump over it and keep running. You will find an area with one orange pipe. Jump in that pipe to advance to World 2.