The Sonic the Hedgehog team have announced that the PC version of Sonic Mania is still undergoing optimization, and will be released later on August 29th.
For those who purchased the Sonic Mania PC Collector’s Edition, you will still receive it in the mail on launch day, however, the code included will not work until August 29th. To compensate, folks who have pre-purchased the game and who own the Collector’s Edition will get Sonic 1 for free on Steam until August 15th.
The console version of Sonic Mania for Nintendo Switch, PS4 and Xbox One are still on track for launch on August 15th.