Sonic Mania’s announcement was met with praise following years of mixed reception for the Sonic franchise. Andrew Goldfarb of IGN stated that the game excited him in a way that Sonic the Hedgehog 4, Sega’s earlier return to the “classic” Sonic style, had not. Alex Donaldson of VG24/7 stated that Sonic Mania was the sequel he had wanted for over 20 years, praising its visuals, music, and the inclusion of obscure Sonic and Sega references. Jack Hamnett of Twinfinite praised the game’s attention to detail and how faithful it felt to the original games, saying that it had the potential to return the series to its “former glory”. Despite having initial doubts following “two decades of disappointing Sonic games”, Nick Robinson of Polygon called Sonic Mania a “revelatory moment” after playing a preview, and said it was his most anticipated game of 2017. Donaldson and Robinson praised Sega’s decision to have fans of the series develop Sonic Mania, with Robinson stating that Sega’s own recent efforts to develop side-scrolling Sonic games, such as Sonic Advance and Sonic the Hedgehog 4, never felt “quite right”.
In September 2016, Sega announced a Sega Genesis-themed collector’s edition for pre-order, containing a 12-inch (30 cm) Sonic statue, a game cartridge cast with a golden ring, and a metallic collector’s card with a download code for the game. To promote the collector’s edition, Sega released a retro-styled infomercial featuring former series art director Kazuyuki Hoshino and social media manager Aaron Webber, based on an American television commercial for Sonic 2. A version for Nintendo Switch will also be released, with Tantalus Media handling the port. At a South by Southwest panel in March 2017, Sega announced that the game would be delayed to later in the year.