Super Mario Bros. · NES walkthrough

World 1

The opening kingdom. Learn stomping, ? blocks, pipes, and the first castle axe. Four stages. Previous and next stage links sit under each area.

World 1-1

Overworld Timer 400

Reach the flagpole. This is the first overworld course.

Run right. Stomp the first Goomba. Hit ? blocks — one early low-left block in the first trio holds the Super Mushroom.
The last tall pipe in the opening stretch drops into a coin room and returns you near the end of the course.
A hidden 1-Up sits above ground near that last pipe. Invisible blocks are real; PixelQuest is not listing every coordinate.
Clear the staircase pits and grab the flagpole.

First Super Mushroom / Fire Flower sequence is in ? blocks, as the NES booklet describes.

Underground Timer 400

Reach the exit pipe to the flagpole, or take the intended Warp Zone instead.

Enter the start pipe into the underground. Piranha Plants hide in pipes — wait them out.
A mid-course pipe leads to a coin room. Optional.
At the moving lifts near the end, the normal path drops into the exit pipe to the flagpole.
Warp Zone (intended): ride the lifts to the ceiling, run right past the exit pipe, and drop into the Warp Zone room. Pipes skip to Worlds 2, 3, or 4.

Minus World is a NES cartridge overflow glitch from clipping the 1-2 exit, not an intended world. Nintendo Classics behavior is UNKNOWN. This walkthrough does not publish a glitch method.

World 1-2 Warp Zone — World 2, World 3, World 4.

Athletic / treetops Timer 300

Cross treetop platforms and moving lifts to the flagpole.

This is a treetop course. Standing room is limited.
Red-shelled Troopas stay on their platform; Goombas will walk off edges.
Horizontal lifts need timing — wait until they are close, then jump.
Flagpole ends the course. Collecting every coin here is one of the documented conditions for a later hidden 1-Up in World 2-1.

Castle Timer 300

Reach the axe on the far side of the bridge.

This is the first castle. Fire-bars rotate over the path. Time runs when bars are horizontal or vertical, then move.
A ? block over a fire-bar holds a power-up. Skip it if you are still learning the bars.
At the bridge: Worlds 1–7 use an impostor, not the final King. Hitting the axe still drops the bridge and clears the castle.
If you have Fire Flower, fireballs can also end the fight. Otherwise jump over or run under when the impostor jumps, then hit the axe.

A Toad is rescued. The princess is not here. That pattern repeats through World 7.