New Super Mario Bros./Developer Oversights

From Hiccup
(Most of the level mapping: Peardian)

World 1-Castle[edit]

Original Course Two Objects Removed
NSMB-3-Cas A3 Hidden Course Features.png NSMB-1-Cas A3 Hidden Course Features-Tiles Removed.png

1-Castle has a large unused grey tile object behind some similar objects.

World 3-A[edit]

NSMB-3-A A2 Hidden Course Features.png
3-A has another Goal Flag outside the view, placed after the used Goal Flag was.

World 6-Tower[edit]

Original Course Two Objects Removed
NSMB-6-T A1 Hidden Course Features.png NSMB-6-T A1 Hidden Course Features-Objects Removed.png

6-T has a mini pipe behind the pipe in the Star Coin room.

World 6-B[edit]

6-B has a Goal Flag below the Midway Point Flag, far below view. It was put into the level before all the other sprites.

World 7-1[edit]

NSMB-7-1 Hidden Course Features.png
7-1 has a tileset version of the squishy cloud platform (as opposed to the actor that uses a flat 3D model) outside the view.

World 8-2[edit]

Original Course Two Objects Removed
256px 256px

8-2 has extra "Mini Mario tile" objects behind the vertical pipe.

Mario vs. Luigi - Ice[edit]

NSMB-I-3(ice) Hidden Course Features.png
In the bottom right-hand corner of the VS. Ice Land level is a small step of blocks. They seem to be a duplicate of nearby steps in the same level. The hidden bricks are after the visible bricks in the list of blocks in the level.