In an enemy course level, if you defeat the enemy and wait about 30 seconds, Nabbit will appear, steal your prize and then jump off screen. If however Nabbit is being played as in New Super Luigi U or either game in the Switch port, the screen will simply fade to black without anything happening.

If the final boss is beaten with Nabbit, he'll make a small cameo as Luigi goes up to Princess Peach, spying on the two of them.

By playing as Peachette in the final level of Peach's Castle, the real Peach will act confused before the fight plays as normal.

In the 1.0 version of the game's Chinese release, the POW Blocks are listed with "]0[" on them instead of "POW". This would later be changed in the 1.0.1 update.

The game's reveal trailer on September 13, 2018 shows Mario being played in the levels "Waddlewing Warning!" and "Larry's Trigger Happy Castle". This is not doable in the final game as those are levels from New Super Luigi U, where Mario is not a playable character.

In this version of the game, the Spin Jump button is the same button as the Jump button. This is a first for the series, where the Spin Jump is usually performed by pressing the trigger buttons or shaking the controller. However, on the title screen, if you hold down the left stick for 3 seconds and press L and R, the Spin Jump button will be reverted back to the triggers, and the Jump button can no longer be used for it. Nabbit's voice will be heard when going to the main menu if the control switch is successful. This control option was not advertised or mentioned at any point by Nintendo, and appears to be an Easter egg.