Super Mario Bros. · NES walkthrough

World 3

Night overworld, first Hammer Brothers, a crowded Koopa course, and another castle. Four stages. Previous and next stage links sit under each area.

World 3-1

Overworld (night) Timer 400

Reach the flagpole. First Hammer Brothers.

A mid-course pipe leads to a coin room (optional).
Hammer Brothers throw hammers in arcs. Do not stand under them. A Star in a nearby brick helps if you find it.
A beanstalk (right brick between two block sets, often reached with a running jump rather than only the springboard) leads to a coin sky. Optional.
Flagpole.

A hidden 1-Up above a bridge is documented as appearing only if you collected every coin in World 2-3 or warped into World 3-1.

Overworld Timer 300

Push through a crowded Koopa/Goomba field to the flagpole.

This course is a long overworld packed with Troopas. Kicking a shell can clear a line of enemies — also easy to bounce into a pit.
A Star in an upper brick helps if you want breathing room.
Near the end, wait out the Piranha Plant, take the coins above the pipe if you want them, then finish to the flagpole.

Athletic / treetops Timer 300

Cross sinking and balance lifts to the flagpole.

Stay on upper islands. Some lower islands cannot climb back.
Some lifts sink under Mario’s weight — jump off quickly.
Balance lifts before the pole: wait until heights match, then jump. A hard running jump can overshoot the pole; if that happens you can get stuck until time runs out.
Flagpole. Coin-complete here is a documented condition for a later hidden 1-Up in World 4-1.

Castle Timer 300

Reach the axe through Podoboo pits and crossed fire-bars.

Time Podoboo pits. Watch paired fire-bars before committing.
A low alcove before the bridge is a pause spot.
Impostor + axe again. Ceiling blocks make jumping the fight riskier than running under or using fireballs.