The forum's resident Sonic fan here. It's quite a timeless IP, and it's criminal that it's only been used for a single scene in a wider dark ride, and on a Maurer Spinner when Sonic games are basically designed full of rollercoaster elements. The problem with the Sonic room was how it was depicted.
The Sega Mega Drive was in its twilight years in 1994, and it's successor The Sega Saturn was released in Japan the same year, and the UK in 1995. 1994 saw two big Sonic game releases on the Mega Drive, which were actually two halves of the same game. Sonic 3 was released in February, the second part Sonic & Knuckles was released in October. The Sonic room in Toyland Tours promoted Sonic 3, and game footage was shown prominently to riders. Bizarrely, the large controller used for theming depicted a 2 button Sega Master System controller, the Mega Drive's predecessor console which was no longer supported by 94.
So the Sonic room was outdated pretty much in its opening year, certainly by the year after. By the time Toyland closed, Sonic himself had been redesigned in 1998 (for the release of Sonic Adventure on the Dreamcast) with the Toyland depiction being his original 1991 design, Sega had released and killed 2 more console generations and exited the console business entirely 4 years prior, and numerous mainline Sonic titles had been released. Charlie opened the year the famously broken Sonic "06" was released, the fifth mainline Sonic title since Sonic 3.