Producer Takashi Iizuka said Sonic Team has no plans to release more episodes in the future.
"We are looking forward to hearing the feedback from the users for Episode 2, but we are currently not planning to release another episode," he told Digital Spy.
Iizuka added: "We just want to see how the users accept this episode."
Although Sonic 4: Episode 1 was released on WiiWare, the sequel will not be available through the digital download service.
Sonic 4: Episode 2 will be available on Xbox Live Arcade, PSN, PC, iOS, Android and Windows Phone later this year.
> Read our full interview for Sonic 4: Episode 2
> Digital Spy's hands-on preview of Sonic 4: Episode 2
Watch a trailer for Sonic 4: Episode 2 below: