After receiving the information of Eggman's plans, leaving Central City, and joining up with Knuckles, Knuckles leads Sonic, Tails, and Amy Rose to Dr. Eggman's pyramid base, where he said he saw Rouge enter the pyramid and assumed Eggman was there too. At this, Tails volunteers to find the entrance to the base.
The stage is inspired from the pyramids of Egypt. The stage is infiltrated with GUN robots especially the Hawks series. The Stage is also is infiltrated with Kiki, Unidus, Gola robots and shifting sands that will make the players loose a life if they fall in.
Collect 100 Rings
This mission can be quite difficult, particularly if the player is trying to score an A rank. Move as quickly as you can, but be careful not to run into any swooping enemies. The one on the path leading to the first checkpoint can be especially tricky. Lock onto him and move left to dodge his fire. Stay along the main path in this stage, but be sure to grab the item boxes in the alcove to the right just before the third point marker.
Find the Lost Chao
The ancient shrine is along the main path after the third checkpoint marker, and is almost impossible to miss. Playing the Mystic Melody near it opens the adjacent door. Walk in and hover to one of the platforms below, locking onto enemies as the player goes. Walk through the doorway down there, and hover over to the pulley. Grabbing the pulley will take the player up in front of a high platform where the small Chao is waiting.
Reach the Goal Within 3:00
Completing this mission can be fairly difficult, but there are a couple of simple shortcuts that can shave substantial seconds off the time.
When the player gets near the shifting sands sections, there are several breakable doors that lead to shortcuts above them.
The player must avoid slowing down for enemies or picking up rings to complete in time.
Clear Hard Mode
The most difficult aspect of this mission is the increase in enemies swooping down from above. They also fire much more rapidly than before. As for the structural changes, there are some pulleys that are missed from this mode, and replaced by other types of pulleys. Additionally, the platforms located above the shifting sands now rotate potentially. Making the player needing to wait for them and jump onto and off as quickly as possible.
Big the Cat sighting
At the beginning of Hidden Base, the player should be able to see two statues covered in scaffolds. On the right statue's scaffolding, Big can be seen sitting there.