One Ring Challenge

One Ring Challenge is a Challenge Act in the console/PC versions of Sonic Generations.

Description
The player takes control of Modern Sonic in Speed Highway. The player is given only one ring at the beginning of the stage, with there being no further rings up ahead in the rest of the stage.

The player is tasked with getting through a certain section of Chemical Plant, with several addition hazards and enemies put in place that aren't usually there in order to make it easier for the player to lose their single ring. The player must make it to the goal with said ring within a given time limit.