Orange Pipe to World 2 in Level 1-2
In level 1-2 after you reach the checkpoint you'll will see three koopas in the next room. Jump to the middle ? box and jump forward face to the wall. You will find a path. Go left to get a 1-up and go all the way right and you will find an orange pipe and it will take you all the way to World 2. This secret is good for kids who just got the game. But you can still try it anyway if you completed the level or the whole game.
Secert 3D Show off
If you wait for the level to finish at the title screen it will take you Somewhere??? Find out for your self.
Spot a UFO
1.go on 1-3
2.look into the binoculars
3.look up in the sky
4.if your lucky, you will see one go past!
World 1-2, right after the checkpoint flag, there are three koopa troopas and three coin blocks. Get on the first long coin block which is on the ground, then simply walk down onto the koopa troopa below when it moves right below the coin block. With a bit of timing and adjusting your position, you'll be bouncing off it repeatedly and start getting 1-ups. If you mess up and die, simply restart from the checkpoint.
One-Up Conversion At The Goal
When you're holding an item, such as the blocks that let you twirl higher in the air, see if you can make it to the goal post without letting them go. If you complete the stage while still holding onto the item, it'll change into an extra One-Up Mushroom.
Maximun number of lives
In this game, you can actually 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 any other place 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.
Hatless Super Mario and little Mario with hat
Once you've reached the maximum number of lives(which is 1,110, displayed by a triple-crown), any time you're in Super Mario(or Luigi) form you'll be without your hat, and vice versa when you're little Mario(Luigi). Note: this doesn't apply to any other form than Super, ie. Fire, Tanooki, Boomerang, etc. This includes the opening demo and "demo room"(when you leave the game untouched for a couple of moments at the title screen).
Stars on your file
If you die less then 5 times in every level the stars will be extra shiny.
star 1 - Defeat bowser in world 8's final level
star 2 - Beat every level as Mario
star 3 - Beat every level as Luigi
star 4 - Collect the gold flag on every level
star 5 - Collect all star coins
Final level - Get 5 stars on your file
How to Unlock
Play as Luigi
Clear Special World 1
Clear World 8