- Cut Song:
- An 8-bit rearrangement of Marble Zone
was found through the game's files, suggesting the zone was meant to be in the game at one point. - The Yuzo Koshiro Early Collection Box released in 2018 features numerous unused tracks that didn't get used in the final game. It's unknown what these tracks were intended for.
- An 8-bit rearrangement of Marble Zone
- Dummied Out: There's an 8-bit rendition of the 16-bit game's Marble Zone theme in the game's data, along with a sprite for that zone's Bat Badnik.
- Late Export for You: The Sega Master System version didn't get released in Japan until 2008 through the Wii Virtual Console, 17 years after its original release.
- What Could Have Been:
- According to Yuzo Koshiro himself, he had adapted the entirety of Masato Nakamura's Genesis score, but only used 3 of the tracks in the final product.
- Marble Zone was originally planned to be a zone, but it ended up getting cut early on in development. However, the rearrangement of the zone's music still remains in the files.
Miscellaneous trivia:
- The US Master System version is literally just the European version with a UPC sticker stuck over the barcode on the back of the box. This was largely due to the Master System being all but discontinued in North America, with Sonic 1 being the last Master System game to be released in the country. As an interesting byproduct of this, it's one of the only classic-era Sonic games released in the US to depict Sonic with his original Japanese design by Naoto Ohshima, instead of the Americanized redesign by Greg Martin.
