World 5-1 (Super Mario Bros.)

World 5-1 is the first level of World 5 in Super Mario Bros. and the seventeenth level overall in said game. This level introduces the Bullet Bill and Turtle Cannon enemies into the series.

Layout
The player starts in front of a row of Koopa Troopas and Little Goombas, ending at pipes with Piranha Plants and a gap between the two. After the second pipe is a row of Little Goombas and Koopa Paratroopas, after which is a block structure with a row of bricks above it, the middle of which containing a Starman. Afterward are more Little Goombas and Koopa Troopas along with the new Turtle Cannon. Beyond the row of enemies is a structure of blocks, and the gap between the bricks and the stone pillar is a Hidden Block containing a 1 up Mushroom. The player can also use the blocks as a platform to reach the Warp Pipe above, which leads to an underground area with coins, and the exit pipe will take them back above ground near where they left. Around the pipes are two Turtle Cannons and beyond those are two Koopa Paratroopas jumping down the stone stairs and floating pillar before the flagpole.

Super Mario Bros. Deluxe challenges
In Super Mario Bros. Deluxe, the player can collect five Red Coins, find a hidden Yoshi Egg, and get a medal based on their score. The Yoshi Egg is found in a Hidden Block between the stone stairs and floating pillar at the end of the level, and the score to beat is 80000. The Red Coin locations are:
 * High above the second pipe
 * In a Coin Block directly to the right of the brick with the Starman
 * Above the gap after the first Turtle Cannon
 * Above the Warp Pipe to the underground area
 * In the Coin Block in the underground area

Trivia

 * At the start of this level, a fortress is seen instead of a castle like with the other first levels in other worlds. This is the case in all versions of the game, including Super Mario All-Stars.

Mondo 5-1 (Super Mario Bros.)