Pyramid Cave is an Egyptian indoors ruin themed level, with large murals and hieroglyphs and since it is a base belonging to Eggman, statues with their heads replaced by one with his face.
The major gimmicks of this level are hourglass doors derived from Sonic & Knuckles's Sandopolis Zone. There are also hoops that, if jumped across, will award Sonic skill points and the only level featuring object-to-place mechanics.
Other level-specific objects include bars that can be swung, torches and bonfires, chimneys with Eggman's face, boat pendulums and windmills. Boos also are around here that can be an obstruction to the player, along with E-1000s.
Collect 100 Rings
The fastest way to collect a hundred rings in this level is to light dash whenever possible, and to make two important stops:
Instead of swinging from the first pole, drop and grab twenty rings from the item boxes below.
In the alcove to the left where the player finds the second Chao Box, collect ten rings from the item box and then smash the crate for twenty more.
Find the Lost Chao
Play the Mystic Melody at the second ancient shrine along the main path to make a spring appear to the right of the player. Bounce up and run down the path until the player comes to an hourglass. Flip it, then do a Bounce Attack up to the pole above. Quickly swing from pole to pole to get across the gap before the door closes. Behind the door, is the lost Chao.
Reach the goal within 4:00
There are no shortcuts in this level, so the player must master this level to come in under four minutes. Grind every rail, swing from every pole, and light dash whenever possible.
Clear Hard Mode
There are a couple of changes in the Hard Mode that make it substantially more difficult than usual:
First, the hourglass in front of the first E-1000 is moved to right, and the spring on the platform above it is gone. Thereby forcing the player to do a Bounce Attack to reach the tunnel above.
The placement of items on the player's way to fetch the second gate key has changed entirely. The hourglass that opens its door is now atop a white ledge, so the player must drop the key in front of the door, and go back to flip the hourglass, then pick up the key again before running through.
Chao Containers locations
When the player sees some poles for the first time in the stage, instead of swinging on them drop down below and look on that platform for the first chao box.
After the player uses the Bounce Bracelet to bounce up to the walls, go forward until you reach another hourglass. Look in the alcove to the left, and the player will see the second chao box.
Play the Mystic Melody near the ancient shrine near the third point marker. Use the Light Speed Dash across the row of rings that appears, and catch a pulley that lifts the player to a platform with another ancient shrine. Play the Mystic Melody again, and light dash while holding up and the player will land on a rail. At the end of the rail, is the third chao box.
The Gold Beetle can be found close to the bottom of the Eggman symbol, on the room with a E-1000 and a three start spring, after the third Checkpoint. In Sonic Adventure 2: Battle, it is moved over to the left.