Ring Time Challenge is the fourth Challenge Act of Sky Sanctuary Act 1 in the console/PC version of Sonic Generations. It is unlocked after clearing every Stage in the classic era and is playable only as Classic Sonic.
The player takes control of Classic Sonic in a highly modified version of Sky Sanctuary Act 1, consisting of many different platforms and pathways filled with enemies. The player is given Ring Time in order to collect enough Rings to complete the Act.
In this Challenge Act, the objective is to reach the Goal Plate after collecting at least one hundred Rings. The Ring Time Challenge provides Sonic with limited usages of the Ring Time Skill to use throughout the act. The player must use this ability to turn nearby enemies in the stage into Rings, which the player needs to collect, as the aim of this challenge is to get at least eighty rings before reaching the end of the stage in order to be successful.