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 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 Act into Rings, which the player needs to collect, as the aim of this challenge is to get enough Ring before reaching the end of the Act in order to be successful.
The player begins the act in the normal starting area, before running into a set of platforms. They must activate a Switch to progress, using Ring Time whenever they see an enemy. From there, the player will continue in the normal direction of the stage, hitting more switches and collecting Rings (both in the stage and from Eggrobos) until they reach the Goal Plate on an elevated section of the Act.