Players control Sonic, Shadow, and the new character Silver, who battle Solaris, an ancient evil pursued by Doctor Eggman.

Each playable character has his own campaign and abilities, and must complete levels, explore hub worlds and fight bosses to advance the story.

Sonic Team sought to create an appealing game in the vein of superhero films such as Batman Begins (2005), hoping it would advance the series with a realistic tone and multiple gameplay styles.

Problems developed after Naka resigned to form his own company, Prope, and the team split to work on the Wii game Sonic and the Secret Rings (2007).

Sonic the Hedgehog received praise in prerelease showings, as journalists believed it could return to the series' roots after years of mixed reviews.

However, it received negative reviews, with criticism for its excessive loading times, camera system, story, voice acting, glitches, and controls.

[1] Like Sonic Adventure, the player navigates through open-ended hub worlds where they can converse with townspeople and perform missions to advance the story.

The main playable characters are three hedgehogs: Sonic, Shadow, and Silver, who feature in separate campaigns titled "episodes".

The rings can protect a character from a single hit by an enemy or obstacle, at which point they will be scattered and blink before disappearing.

[3] Doctor Eggman kidnaps Princess Elise of Soleanna in the hopes of harnessing the Flames of Disaster,[c] a destructive power sealed inside her.

[c] When Mephiles meets survivors Silver and Blaze, he fools them into thinking Sonic is the cause of the destruction, and sends them to the present to kill him.

Throughout the story, Sonic and friends travel between the past, present, and future in their efforts to stop Mephiles and Iblis and protect Elise from Doctor Eggman.

They travel ten years in the past and learn that Mephiles seeks to bond with Iblis, who was sealed within Elise as a child, as they are the two halves of Soleanna's omnipotent god, Solaris.

Mephiles eventually succeeds after killing Sonic to make Elise cry over his death, releasing her seal on Iblis and merging with him with the use of Chaos Emeralds to become Solaris, who then attempts to consume time itself.

The heroes and Elise respectively collect and use the power of the Chaos Emeralds to revive Sonic, and he, Shadow, and Silver transform into their super forms to defeat Solaris.

Sonic and Elise are brought to the past and extinguish Solaris' flame, removing the god from existence and preventing the events from ever occurring.

When Sega reassigned the team to start working on a new game in the bestselling Sonic series, they decided to retain the realistic approach.

[14] Series co-creator and team lead Yuji Naka wanted the first Sonic game for seventh-generation systems to reach a wide audience.

[23] As the hardware of the Xbox 360 and PlayStation 3 was more powerful compared to the prior generation's consoles,[9][15] the design team was able to create a more realistic setting than those of previous Sonic games.

[25] Nakamura and producer Masahiro Kumono reasoned this was because the characters would be interacting with more humans, and felt this would appeal to older players.

[25] They felt Sonic Heroes (2003) and Shadow the Hedgehog (2005) had veered into different directions and wanted to return the series to its speed-based roots in new ways.

For example, they wanted to include multiple paths in levels, like the Genesis games had, a goal the realistic environments helped achieve.

[14] Silver the Hedgehog's gameplay style was born out of Sonic Team's desire to take advantage of Havok's realistic physics capabilities.

[35] The score was primarily composed by Tomoya Ohtani along with Hideaki Kobayashi, Mariko Nanba, Taihei Sato, and Takahito Eguchi.

[36] The main theme, the fantasy-rap song "His World", was performed by Ali Tabatabaee and Matty Lewis of the band Zebrahead.

[38][42] Vocal Traxx: Several Wills contains seven songs; four are from the game, while the remaining three are remixes, including a version of "His World" performed by Crush 40.

[3][74][75] GamesRadar considered it overwrought[78] and "conceptually challenged",[79] and Eurogamer found its voice acting painful and its cutscenes cringeworthy.

[4][8] Game Informer described it as ambitious and praised the graphics, story, amount of content and replay value, but believed only Sonic fans would enjoy it.

[4] Halverson initially gave the Xbox 360 version 9.5/10, praising each character's controls and abilities and calling it the best 3D Sonic game yet.

[101] A second team of fans, led by ChaosX, began developing a separate PC remake in Unity, Sonic P-06, releasing multiple demos from 2019 onward.