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.
Story
After Sonic comes to a standstill fighting against Shadow, 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 Tails and Amy to get off the island. Shadow leaves, and Sonic has exactly eight minutes to escape.
Gameplay
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Most of the stage takes place in a forest. There are several types of branches to be swung on.
Overview
1st Mission: Escape from the Island in 8 minutes!
Sonic must escape from the forest within eight minutes to get off the island. This is plenty of time to accomplish the mission and get the Ancient Light from here.
2nd Mission: 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 many G.U.N. robots that tend to appear right on top of him.
3rd Mission: Find the Lost Chao!
In addition to the Mystic Melody, Sonic will also need the Bounce Bracelet from Pyramid Cave in order to complete this mission. Right before the third Point Marker, Sonic must quickly jump onto a platform and jump off backward to end up on a platform with the Ancient Ruin on it. Sonic can then play the Mystic Melody to make platforms appear, which requires the Bounce Attack to reach them. After that, Sonic must use the Homing Attack across a series of Mono Beetles to get to the platform with the lost Chao on it.
It is also possible to complete this mission without either Level Up Item if he charges a Spin Dash up the slope just before the third Point Marker, then has him jump at the right point to gain enough height and in close proximity to one of the Mono Beetles with a Homing Attack.
4th Mission: Reach the goal within 4 minutes 0 seconds!
This mission is fairly simple, as Green Forest itself can be completed within just over three minutes.
Last Mission: Clear Hard mode!
Green Forest undergoes some changes that make it a little tougher to complete. The long vine runs are now lined with Iron balls and the platforms at the end sink much faster. The Bounce Bracelet will make this stage slightly easier to complete.
Level Up Item
The Level Up Item in Green Forest is the Ancient Light. After the second Vine that Sonic swings on and past the second loop, the player must hit the Springs and land on the 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 then go to the nearest edge, and a Mono Beetle should appear. The player must then use a number of Homing Attacks on it and the Item Boxes that appear behind it to reach another platform, where the Ancient Light is located.
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. It is accessed by Somersaulting through the small gap to the right of the Rhino Spike.
After the second Point Marker, the Chao Container can be found on a lower platform between the two larger platforms in that area.
After the third Point Marker, the final Chao Container is found on the third platform with a Spring on the upward path.
After the second Point Marker and past the Vine, the player should move to the other side where the third Point Marker is and Spin Dash up the hill 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.
After the 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 Container in this stage contains a Half Fish, but only if the previous two Chao Containers were opened already.
