This is an odd landscape with many factory buildings under the influence of Eggman Army adjacent to the Arsenal Pyramid. It seems that a powerful defense robot is also being built. So be careful! — Sonic Forces Japanese Twitter
Guardian Rock is an industrialized area in the once prosperous, now-turned-desert Green Hill area. The Zone's ground is covered in green-striped grass that moves with the wind, and the soil itself is covered in checkerboard patterns in different shades of brown. However, the plants are shown to have dried out in various places, and the soil have in many locations assumed a sandy hue. Also, the area has been facilitated with semi-industrial platforms and Badniks all around.
A giant Death Crab lurks in this area, which be can be seen crawling around in the background at various points.
While the Avatar makes their way through Guardian Rock, the Resistance are notified of the menacing Death Crab that protects the facility in the proximity, which the Resistance soldiers cannot handle at the moment. After Amy has conducted an analysis of the robot, Knuckles the Echidna advises the Avatar to divert the Death Crab's attention and just run rampant through Eggman's forces.
Completing their mission, the Avatar is told to head back, only for the Death Crab to arrive and chase after them. However, the Avatar is able to stop the gigantic robot and make their escape.
For the majority of this stage, the Avatar traverses a 2D sidescrolling area. In terms of layout, the stage is pretty straight forward, as it consist of a fairly straight main path with few alternate paths along it. Lots of Rings and Wisp Capsules are abound to help protect the player during this stage. Clusters of Rings can also be found in midair, which serve as guides to upper paths or Red Star Rings.
Unique obstacles in Guardian Rock are the Death Crabs' legs, which are encountered at various points. These legs periodically stomp into the ground or platforms, crushing anyone that get caught underneath them.
When the stage begins, the only direction the player can move is right. Keep moving in that direction on the main path to eventually arrived at the end of the stage. Along the way are areas both above and below the main path that the player can reach through the use of the Wispon, although most of them are short and ultimately rejoin the main path.
Near the end of the stage, the Death Crab will start chasing the player down. During this section, the perspective changes and the player is stuck running forward towards the screen while the Death Crab chases after them from behind. The player is unable to attack the Death Crab however, while it is able to fling rocks at the player, each of which can inflict damage should they hit. To win this battle, the player must avoid the rock blocks thrown with the Quick Step until a Real-Time Interaction appears. Executing it successfully makes the Avatar swing around the Death Crab while they wrap its legs up with using their grappling hook; the better the player times the Real-Time Interaction by initiating it when the green rings that appear overlap, the greater the point bonus the player will receive. As the Death Crab trips and falls in defeat, the player will reach the goal.
↑Sonic Forces on Twitter(Japanese). Twitter. Sega (20 October 2017). Retrieved on 21 October 2017. “【ガーディアンロック】 アバターが単独でミッションに挑むステージの「ガーディアンロック」。ここはアーセナルピラミッドとも隣接するエッグマン軍の勢力下で、多くの工場施設が建設されて異様な景観となっている。強力な防衛ロボも配置されているようなので注意して進もう！”