World 3-1

All block backgrounds in World 3 were replaced with waterfall backgrounds.

World 3-2

The rail lift ends with a straighter path under the blocks and coins, which were moved down.

World 3-3

This part in SMA4 has a shorter gap between the square platform and the next one. In addition, one brick block was moved up.

One block added in the corner of the "L" makes it easier to jump away from Boss Bass should you fall between the pipe and the blocks.

World 3-4

The first two small hills moved down by one block. As previously mentioned, Lakitu is always one block lower in the SMA4 version.

World 3-5

A hidden 1-Up was added at the beginning of the goal area. Once again we see the block-style background replaced by the waterfall background.

World 3-6

The SMA4 version has several changes around the exit pipe. The Rotary Lift was moved down and left, the pipe was moved right by one block, and two wood blocks were attached to the pipe.

World 3-7

In the background, which was moved up a little, all the clouds now go in front of the hills. The Question Block at the beginning was moved down, probably to keep space between it and the top of the screen.

The tallest grass platform in the stage was lowered one block.

After the grass platform on the left, the shrubbery, bricks, wood block, and platform on the right were all shifted left by one.

The top platform here was moved down by one block.

A few blue blocks were added to the right side of the block structure near the goal.

World 3-9

All block backgrounds in World 3 were replaced with waterfall backgrounds.

The SMA4 version has a thicker division between the land and water sections.

World 3-Fortress 2

In SMA4, the starting room was shortened and doesn't scroll horizontally.

The pipe and floor before the staircase were lowered.

Everything in the second half of the Stretch room was lowered by one, perhaps to keep the screen from scrolling vertically there.

World 3-Airship

The first piece of the rope handrail was removed, and a Question Block containing a Super Leaf was added at the end.