As with Sonic 2 (1992), players can play as Sonic and Tails simultaneously, or a second player can control Tails independently. Players select one of 3 playable characters, each with their own unique abilities: Sonic can perform a 'drop dash' which sends him rolling in a dash after a jump, Tails can fly and swim, and Knuckles can glide and climb walls. Sonic Mania is a side-scrolling platformer similar to the early Sonic the Hedgehog games released for the Sega Genesis. Gameplay screenshot showing Sonic in Studiopolis Zone, the first of five original levels in Sonic Mania Sonic Mania Plus, an enhanced version with additional content, was released in July 2018. Within a year, it had sold over one million copies worldwide. Several described it as one of the best Sonic games and one of the best games of 2017. Its presentation, level design, music, and faithfulness to the early Sonic games were praised, but its lack of originality was criticized.

Many reviewers saw it as a return to form for the Sonic series following a number of poorly received games released after the 1990s. Sonic Mania was released in August 2017 and became the highest-rated Sonic game in fifteen years. The team used Whitehead's Retro Engine and aimed for a graphical quality between Genesis and Sega Saturn games. Art, level design, audio, and additional programming were provided by independent studios PagodaWest Games and Headcannon. Development began after lead developer, director and programmer Christian 'Taxman' Whitehead, who was previously contracted by Sega to develop enhanced mobile ports of Genesis Sonic games, presented a playable prototype to Sonic Team producer Takashi Iizuka. The development team was composed of members known for their work in the Sonic fangame and ROM hacking community. The story follows Sonic, Tails and Knuckles as they venture to defeat their nemesis Doctor Eggman and his robotic henchmen, the Hard-Boiled Heavies. It takes place over 13 levels, including several redesigned from past games. Produced in commemoration of the Sonic the Hedgehog series' 25th anniversary, Sonic Mania pays homage to the original Sega Genesis Sonic games, featuring speedy side-scrolling gameplay. Sonic Mania is a 2017 platform game published by Sega for Nintendo Switch, PlayStation 4, Xbox One, and Windows.

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