After Mario obtains the first Power Star, when the message suggests out of the two options to go to The Princess's Secret Slide, it erroneously states that it's on the second floor. It's actually on the mezzanine of the first floor. The actual second floor is a circular corridor led from the spiral staircase leading to it from the keyhole door on the mezzanine.
The steel doors in the game typically have a different sound effect than the wooden doors, including in the course Hazy Maze Cave. However, the once-submerged steel door after Mario pounds on the two pillars that drains the moat when he goes through it has the sound effect of wooden doors.
When the player talks to Yoshi on the roof of the castle in the courtyard, a spelling error can be seen in Yoshi's dialogue, with the first line of text reading "Mario!!! It that really you???" It should be "Mario!!! Is that really you???"
On the course Shifting Sand Land that takes place on a desert based upon Ancient Egypt in the Sahara, an enemy named Klepto is a condor. Condors live in North America, not in the Sahara.