From Sonic Retro
The Flame Ring is an upgrade available to Sonic the Hedgehog and Shadow the Hedgehog in Sonic Adventure 2. It upgrades the duo's Somersault attack into the Fire Somersault, which allows the hedgehogs to break not only wooden crates, but steel crates as well. Black metal crates are still unbreakable, however. This upgrade is required to complete Sonic's story-related missions, but is optional for Shadow.
Sonic the Hedgehog
- Purpose: Allows Sonic to break steel containers with a Somersault or Bounce Attack.
- Location: Crazy Gadget. After going past the second Point Marker, jump into the high-speed warp tube. Keep going until you reach the end of the room. Then back track while the gravity is at its normal setting. Use a spring to get up on to the stage where the Flame Ring is.
- Requirements: None.
- Required For: Completing Crazy Gadget, which makes it the only one of Sonic's upgrades to be truly intractable during story mode.
Shadow the Hedgehog
- Purpose: Allows Shadow to break steel containers with a Somersault.
- Location: Radical Highway. After using a pulley and a spring to make it up two platforms, turn left instead of going right. Somersault under the barrier, cross the gap (a ring chain is present to Light Dash across), and use the spring to reach the platform with the Flame Ring.
- Requirements: None. The upgrade is immediately preceded by a chain of rings that you're meant to have the Air Shoes to cross, but the gap is small enough that jumping it without a light dash is comparatively simple.
- Required For: Nothing--there's one part in the final mission of White Jungle where Shadow is faced with a blockade of metal boxes, but it's possible to squeeze around the sides. Nothing else even comes close to requiring this item.