Challenge Mode:
Once you've beaten the game go to the world map it doesn't matter
which world. Then press the start button to have the pause menu coming up.
Now press the following buttons in the exact same order to activate the
secret challenge mode. L, R, L, R, X, X, Y, Y(these are the buttons
you have to press). One the Challenge Mode is activated enter a level
of your choice doesn't matter which one. You'll notice that the screen
will scroll through the level so that means that you can't return if
you missed some coins or something. To de-activate the challenge mode
repeat the same procedure as described above.
1-UP Mushrooms:
1-UP Mushrooms can be found by hitting/smashing blocks.
They give Mario an extra life.
Blue Koopa Shells:
You can win Blue Koopa Shells in Red Toad Houses. They give
Mario a shell on his back, where he can dodge enemy attacks.
Coins:
Coins can be found in the open or hiden within blocks.
You also recieve 1 coin for each enemy you kill with fire balls.
When you get 100 coins, you get an extra life.