The stage is similar to Shadow's White Jungle in appearance, as they both take place in the jungle. The stage is occupied by G.U.N. robots, and there are also hidden locations within.
After Sonic the Hedgehog comes to a standstill fighting against Shadow the Hedgehog, Shadow gets a call from Dr. Eggman, who tells him that Prison Island is about to blow up. Upon hearing this, Sonic realizes that he needs to save Amy and Tails and get off the island. Shadow leaves, and Sonic has exactly eight minutes to escape.
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Near the end of Green Forest, the platforms in the jungle will fall, and the player must be careful not to drop into the water
Level Up Item
The Ancient Light is located here. After the second time Sonic needs to swing on vines and after coming through the second loop (half loop), he must hit the springs and land on the desired platform. Once on this platform, the player must go to the right, where there will be an Item Box with 10 Rings. The player must go to the nearest edge, and a Mono Beetle should appear. The player must then use a series of Homing Attacks on it and the Item Boxes that appear behind it to reach another platform, where the Ancient Light is located
Escape from the island in 8 minutes
Sonic must escape from Green Forest within eight minutes. This is plenty of time to accomplish the mission, and Sonic can get the Ancient Light from here.
Collect 100 Rings
This 100 Ring mission is not very difficult, as most of the rings are placed in a straight line. Sonic must avoid the constant spawn of G.U.N. robots that tend to appear right on top of him.
Find the Lost Chao
In addition to the Mystic Melody, Sonic will also need the Bounce Bracelet from Pyramid Cave first in order to complete this mission. Right before the third checkpoint, Sonic must quickly jump onto a platform and jump off backward to end up on a platform with the Ancient Shrine on it. Sonic can then play the Mystic Melody to make a platform appear. Sonic must use the Bounce Bracelet to bounce himself onto the platforms carefully and Homing Attack some enemies to get to the platform with the lost Chao on it.
Reach the goal within 4:00
This mission is fairly simple, as Green Forest itself can be completed within just over three minutes. Sonic will also have time to collect points to earn an A rank.
Clear Hard mode
Green Forest undergoes some changes that make it a little tougher to complete. One is that the long snake runs are now lined with spike balls, and the second is that near the end with the shifting land, the platforms sink much faster. Sonic will then need to jump over the spike balls and jump higher over the sinking platforms to make it through this level. The Bounce Bracelet will make this stage slightly easier to complete.
Chao Container locations
At the beginning of the stage, the first Chao Container can be found in a secret room halfway down the long tunnel. This room is accessed by Somersaulting through the small gap to the right of the Rhino Spike.
After the second Point Marker, the second Chao Container can be found on a lower platform between the two larger platforms in that area.
After the third Point Marker, the third Chao Container can be found on the third platform with a Spring on the upward path.
After the second Point Marker and after riding a swinging Vine to the place with floating platforms, the player should move to the other side where the third Point Marker is and Spin Dash from the downhill back to reach a small floating platform above. They must then charge a Spin Dash and release the button to the left to reach the platform where Big is fishing.
Post-boss battle in the scene where Sonic and Shadow are panting, if the player pays close attention, they will see that they are near the mid-section of Green Forest's level layout.
The third Chao Box in this stage contains a Half-Fish, but only if the previous two Chao Boxes were opened before opening the third box.