Sonic Mania Game Keys

Go to: http://store.steampowered.com/ and download STEAM client
Click "Install Steam" (from the upper right corner)
Install and start application, login with your Account name and Password (create one if you don't have).
Please follow these instructions to activate a new retail purchase on Steam:
Launch Steam and log into your Steam account.
Click the Games Menu.
Choose Activate a Product on Steam...
Follow the onscreen instructions to complete the process.
After successful code verification go to the "LIBRARY" tab and start downloading.

Sonic Mania Encore DLC - Experience a new take on familiar zones with the all-new Encore Mode, play as two new characters with their unique abilities: Mighty the Armadillo, and Ray the Flying Squirrel, and compete with up to four friends in expanded Competition Mode!