Flame Shield Challenge is the fourth Challenge Act of Crisis City Act 1 in the console/PC version of Sonic Generations. It is unlocked after clearing every Stage in the Modern era and is playable only as Classic Sonic.
This Act takes place within a slightly modified version of Crisis City Act 1. Platforms have been moved around, and there are more fire-based hazards. Flame Shield Monitors have also been placed frequently in the Act, as they must be used to bypass the firey obstacles and narrow Spike traps.
In this Challenge Act, the objective is to reach the Goal Plate at the end of the course.
The player begins on a raised section of road, and mostly travels through the stage as normal. They will soon reach the circular tower, and will need to go to the right side of it, drop down, and go left to find a spring which will take them to the upper level. After going to the right and heading down the fallen building, the player will need to travel upward through the skyscraper using catapults and the Flame Shield's jump dash. Near the end, there will be several long rows of spikes which the player must dash through in order to pass by safely, and will find the Goal Plate at the right of the highest level.
As long as the player does not lose their Flame Shield, they can move through the Act without stopping and reach the Goal Plate quickly.