The Baby Yoshi seen in an egg half hatched on the game's Japanese title screen has an unused graphic of it's full body, suggesting that the game was originally intended to show Baby Yoshis both fully hatched and half hatched.

Within leaked source code for Pokémon Black and White uncovered by the Teraleak (a large-scale breach of internal server data from Game Freak in 2024) is an unreleased Nintendo DS remake of Yoshi, which according to the commit notes was intended to test multiboot functions for the two games. Various traits in the remake suggest that it was ported from a prior attempt at a Super Nintendo Entertainment System version instead of being made with the DS in mind: its name on the title screen is Super Yoshi no Tamago, while its copyright notice is listed as 1995 and credits Ape Inc., which had shut down in the same year. Furthermore, gameplay takes place exclusively on the bottom screen, and there are no touch control features present.

The remake only has one stage, an underwater level. Mario uses Jill's voice lines from Drill Dozer while Yoshi retains his modern voice. The game is also riddled with bugs, featuring corrupted title screen graphics, a nonfunctional mode selection screen, and a glitch where the game may lock up if certain button combinations are pressed. Due to the Teraleak only containing fragments of the Pokémon Black & White source code, it is unknown if these bugs reflect the state that Super Yoshi no Tamago was in when it was abandoned.

Yoshi was Game Freak's first collaboration with Nintendo. Nintendo sent an offer to Game Freak to develop the game after originally turning down Game Freak's proposal to publish their debut NES title Mendel Palace two years earlier, as they were not a formally incorporated game company at the time.