Super Mario Land

Super Mario Land is the first portable game in the Mario series, as well as that time Mario cheated on Princess Peach with Daisy.

Unused Music
The ladder-climbing track is much longer than it needs to be, running about 7.7 seconds even though only the first 2.2 are heard in normal play. The following Game Genie codes will play the song at World 1-1 depending on which version you have:

Audio
The death jingle and goal fanfare had a noise percussion track added in v1.1.

The very first bass sound in the background music in 1-1, 1-2, 1-3, 3-1, 3-2, and 3-3, present in both audio channels in v1.0, was moved to the right channel in v1.1. The bass sound change is more notorious in the autoscrolling stages (2-3 and 4-3), as it affects the whole track.

Screen Wraparound Glitch
There is a glitch that allows Mario to wrap around the screen on autoscrolling levels by holding Left while he is getting pushed offscreen. This was fixed in v1.1.

Falling Enemy


There is an enemy placed right above a pit in World 3-2. If you're quick enough, you can just barely see it as it falls to its doom.

Hidden Platforms


There are falling platforms placed inside the floor in some levels. This may suggest that the level layouts were changed at some point, but certain sprite layouts were not adjusted to match.