Sega Sonic Mania Plus

Sonic Mania is a side-scrolling platformer similar to the early Sonic the Hedgehog games released for the Sega Genesis and Sega CD. 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. As with Sonic 2 (1992), players can play as Sonic and Tails simultaneously, or a second player can control Tails independently. Unlockable options include Sonic's abilities from Sonic CD (1993) and Sonic 3 & Knuckles (1994) in place of the drop dash and "& Knuckles" mode, which allows simultaneous control of any character and Knuckles, including himself.

An expanded version of the game, Sonic Mania Plus, was released in North America and Europe at retail and as downloadable content for the original version on July 17, 2018, and in Japan on July 19, 2018. A version for Amazon Luna was released on October 20, 2020. It adds playable characters Mighty the Armadillo and Ray the Flying Squirrel from the 1993 arcade game SegaSonic the Hedgehog, each with unique abilities: Mighty can slam the ground and is immune to spikes when in ball form, while Ray can glide without losing altitude. Plus also adds an "Encore Mode" with remixed levels and a reworked lives mechanic, a pinball bonus stage, and a four-player competition mode. Additionally, an update released alongside Sonic Mania Plus adds more cutscenes and a reworked Metal Sonic battle based on his appearance in Knuckles' Chaotix (1995). The physical version was released with a 32-page art book and a reversible cover in the style of Genesis or  Drive boxart covers, depending on the region. A soundtrack CD was included with the Japanese physical release.

In an interview with Famitsu, Iizuka explained that Sonic Mania was not intended to have a physical release; Sega staff requested one, but a retail version would have presented a challenge for the production schedule. After the game launched, fans also expressed interest in a physical version. As a retail release would cost more than the downloadable version, the team added value with new content. Mighty and Ray were included because they were rarely featured in games; to accommodate them, level designs had to be altered. Additionally, the multiplayer mode was updated because of the increased number of selectable characters.