DEVELOPMENT

Conception

Following the release of Sonic Forces (2017), Sonic Team began exploring approaches for its next Sonic the Hedgehog game. In addition to celebrating the series' upcoming 30th anniversary, Sonic Team also sought to define what a modern Sonic game should be and solidify the series' direction for the next decade.

Design

The designers focused on transitioning Sonic's speed and abilities to an open-world design while remaining true to previous games, and opted for a mysterious tone to reflect Sonic exploring an unfamiliar landscape. Iizuka felt Sonic's essence as a 3D action game separated Frontiers from adventure and role-playing games such as the Legend of Zelda series. As such, he declined to call it an open-world game, preferring the term "open zone". Sonic Team applied lessons learned from developing Sonic Adventure's hub worlds when designing Frontiers, and repeatedly tested how fast Sonic could race through the open world to determine how large it needed to be. Iizuka said the largest challenge was ensuring that fast-paced exploration would be fun. Sonic Team sought to address criticism that previous Sonic games were too short, and chose not to raise the difficulty level as the game progresses since the open world would provide plenty of content.

Writing

Ian Flynn, who wrote Sonic the Hedgehog comics published by Archie Comics and IDW Publishing and episodes of the Sonic Boom TV series, wrote the script. Iizuka asked Flynn to write Frontiers after reading his work on the IDW comics. He felt Flynn understood the Sonic cast and would bring "a great improvement to the characters' emotions and dialogue". Iizuka noted that the story differs from previous Sonic games in that it is less humorous and does not make the player's goal obvious, instead challenging them to figure out how to solve problems themselves.

Music

Musician Tomoya Ohtani was the lead composer for the game. In accordance with the tone, the Frontiers soundtrack is less upbeat and is "focused more on helping to create a mysterious feeling surrounding the islands. The main theme, "I'm Here", was composed by Ohtani with vocals and lyrics by Merry Kirk-Holmes of the Australian metal band To Octavia, and plays during the second phase of the battle against Supreme, the fourth and final Titan of the game. Japanese rock band One Ok Rock wrote and performed one of the three ending themes, "Vandalize", which also appears on their tenth studio album Luxury Disease. Sleeping with Sirens vocalist Kellin Quinn appears on three Titan battle themes; "Undefeatable", "Break Through It All" and "Find Your Flame", with Tyler Smyth of DangerKids being featured on the latter track. The other two ending themes are "Dear Father" and "One Way Dream", performed by Quinn Barnitt and Nathan Sharp respectively. The latter song plays in place of "Vandalize" if the game is completed with the difficulty set to Hard. The soundtrack album, officially named Stillness and Motion, features 150 tracks, spanning 6 hours and 37 minutes, making it the longest soundtrack in the series. The soundtrack was released on December 7, 2022.