World 1-4 (New Super Mario Bros.)

World 1-4 is the fifth level of World 1, and subsequently, of New Super Mario Bros..

Layout
This level is a grassy meadow, much like World 1-1. The first ? Block (which is on the ground, and not floating, unlike most ? Blocks) contains a Super Mushroom or Fire Flower. A ? Block containing a Mini Mushroom is later found in the level. The Mini-Mushroom can be used to travel into a small pipe nearby that lead to the first Star Coin. A wall made up of Brick Blocks and cement blocks are blocking a Pipe. The wall is shaped in such a way that it's possible to throw a Koopa Shell on it, which will break all of the Blocks and will eventually allow the player to enter it. Alternatively, the player could use a Mega Mushroom to break the block Wall, although the Pipe could end up being accidentally broken, but it's also easy to just Ground Pound them. The pipe leads to a cave that contains a Star Coin that is reached by using a P-Switch that turns every Brick Block into a coin and vice-versa. The third Star Coin is found in a small gap just before the level's Flagpole that is only accessible by Mini Mario, Shell Mario, or Mario without a Super Mushroom.

Infinite 1-Up Trick
This level possesses one of the few places in the game where it is possible to generate an infinite number of Extra Lives. The Koopa Troopa just before the Block Wall, marching on top of four blocks, must be used. Jump on it and grab the shell. Carry the shell over the block wall and continue right, carefully avoiding Goombas, until passing over a short green pipe just over the lip of a small cliff. Immediately past the green pipe is a small hill; walk to the top of the hill, at which point the player can just see a horizontal yellow pipe with Goombas coming out of it on the right side of the screen. Release the Koopa Shell while standing at the top of this hill and allow it to bounce back and forth, jumping each time it goes so that Mario won't get hit. Goombas will continue to emerge from the yellow pipe on the right, and the number of points each time a Goomba is hit will climb until every hit results in an Extra Life. It is possible to collect up to 99 Extra Lives, the maximum allowed in the game. (Note: It does not appear to be possible to do this trick by spinning between the pipes using Shell Mario, as Shell Mario only scores a fixed 200 points per Goomba hit; the points per hit will never grow past 8000 to the Extra Life per hit.)

Star Coins

 * Star Coin 1 - Use the Mini-Mushroom in the ? Block to enter the Mini-Pipe to the left. The coin should be in plain sight.
 * Star Coin 2 - Near a mass of blocks is a pipe blocked by a Brick Block. Break it and find the hidden P-switch to turn the coins into blocks to make steps for the Star Coin. Only Super Mario, Fire Mario and Shell Mario can reach it.
 * Star Coin 3 - The third Star Coin is found in a small gap just before the level's Flagpole that is only accessible by Mini Mario, Small Mario, Shell Mario, or by sliding down the nearby slope.

Enemies

 * Goombas
 * Green Koopas
 * Green Koopa Paratroopas
 * Red Koopas