The first Sonic the Hedgehog movie was originally meant to release on November 8th, 2019. A poster was initially revealed on December 9th, 2018 teasing the design in the movie, leading to mixed and mostly negative responses. A trailer for the film was uploaded on April 30th, 2019, leading to even more negative criticism from both Sonic fans and general audiences alike. Due to the backlash, the film was delayed to February 14th, 2020 and was teased with having a new design for Sonic made by Tyson Hesse, an artist for the Sonic series who had worked on Sonic Mania, Sonic Mania Adventures, Team Sonic Racing Overdrive, and other Sonic projects.
After a delay to February 14th, 2020, a new trailer was uploaded on November 12th, 2019 featuring Sonic's new design, leading to a positive response. The movie follows Sonic coming to Earth and living on his own for 10 years until being caught by Tom Wachowski, a local sheriff in Green Hills, Montana. Sonic's activities caused him to be noticed by the US government, and they have enlisted the help of Dr. Robotnik, a crazed scientist, to catch him. Tom and Sonic team up to defeat Dr. Robotnik and find Sonic's bag of portal rings.
Sonic the Hedgehog 2 released on April 8th, 2022. The plot of the movie takes elements from the game Sonic the Hedgehog 2, released in 1992, but is mainly an adaptation of both Sonic the Hedgehog 3 and Sonic & Knuckles, both released in 1994.
After Dr. Robotnik gets banished into another dimension on a mushroom planet, Knuckles the Echidna discovers him and Robotnik tricks him into thinking Sonic is an enemy trying to steal the Master Emerald, a prized possession by both the hedgehogs and echidnas where both Sonic and Knuckles had originated. Tails the Fox, an avid fan of Sonic who had been watching him through his many gadgets, makes his way to Earth to warn Sonic, eventually teaming up with him. The 4 of them discover where the Master Emerald is located, but Robotnik gets ahold of the Master Emerald and double-crosses Knuckles, meaning him, Sonic, and Tails have to team up to stop Robotnik.
Knuckles released as a 6-episode miniseries on Paramount+. The series follows Knuckles training Wade, a supporting character who is also a sheriff working along with Tom, to become an "ultimate echidna warrior" (he's just training him to be good at bowling.)
The series received mixed reception, mainly stemming from the fact that the series did not focus on Knuckles as the show title might suggest. In my opinion, the show was a fun watch but it had many issues.
Sonic the Hedgehog 3 is yet to be released, scheduled to come out in theaters on December 20th, 2024.
From the post-credits scene and other promotional material that have come out prior to the movie's release, we can infer that the movie will mainly be based on Sonic Adventure 2, released in 2001, as Shadow the Hedgehog is an important character introduced in the game and in this movie.
A trailer is rumored to come out Tuesday, August 27th, 2024 (which is tomorrow at the time of writing this.)