Sonic Mania is arguably one of the most beloved modern Sonic titles at the moment, bringing back the art style so many grew up with and loved. It was widely rumored that Sonic Team and Sonic Mania developers Christian Whitehead, Headcannon, and PagodaWest Games were in talks to potentially develop a sequel given the first's success, but it seems like those negotiations went south upon the announcement of Sonic Superstars and Whitehead's next project Penny's Big Breakaway.
However, Sonic Team head Takashi Iizuka and Christian Whitehead recently talked to Game Informer about why a Sonic Mania sequel never happened despite critical and commercial success. A lot of reasons were given, though one that will undoubtedly cause a bit of a stir among Sonic fans was Sonic Team's insistence that the next Classic game in the series needed to incoporate 3D elements.
In the interview, Iizuka explained that Sonic Team wanted to move away from pixel-art graphics to try and appeal to a wider audience. He believes that pixel art games like Sonic Mania appeal only to a "very specific core audience" and that he wanted the next Classic Sonic game to reach "as many people as possible".
"We wanted to bring this game to as many people as possible and in order to really make it look and feel as appealing to a wider audience, we needed to use the 3D assets to really give it that current look," says Iizuka. "But we do know that core fans want that old Classic Sonic look, they want that old classic Sonic feel, so we focused on making sure the controls were solid and the look and the feel was really representative of a classic Sonic game."
Whitehead also backs up this reasoning when recalling his version of events, claiming that while Sonic Mania 2 was never actually considered in development, the team played around with the idea of a hand-drawn 2D art style and created "a cool Sonic prototype that played with depth in 2.5D". This prototype was then taken over by developer Arzest after Sonic Team and Whitehead parted ways, eventually becoming what we now know as Sonic Superstars.
As for why he and Sonic Team split, Whitehead was quick to debunk the rumor that it was due to a falling out, and claimed that he maintains "a friendly relationship" with both Sonic Team and Sega. While it's nice the two still get along and there's no bad blood, it does sound like those still holding out hope for a Sonic Mania sequel will have to settle for Sonic Superstars. Thankfully, it does look fantastic, and is releasing later this year on pretty much all platforms.