The Action Gauge, also called the Chaos Gauge in Shadow's case and Super Gauge in the Super State, is a game mechanic that appears in Sonic the Hedgehog (2006). It is a gauge that measures the amount of special power the playable character holds.
The Action Gauge consists of an oblong rhombus with a gauge inside it, which can be filled with a cyan-glowing bar representing the available power. Located in the right proportion of the Action Gauge is a 3-light display called the Level Indicator.
The Action Gauge's function is to depict the energy available for the player to perform certain actions, such as Sonic's Energy Field, Shadow's Chaos Boost and Silver's Psychokinesis. Using these actions depletes the power depicted in the Action Gauge and once it empties, they can no longer be performed. All three characters can refill the Action Gauge by collecting Chaos Drives, Gauge Ups and Light Cores, though Sonic and Silver's Action Gauge automatically restore themselves very fast over time (In Silver's case, it will only restore if he is on the ground).
The Level Indicator serves an additional function to Shadow. For Shadow, the light display shows which Chaos Boost level he is currently on, which is indicated by how many of the three lights are glowing red. Note that the higher the Chaos Boost level is, the faster will the Action Gauge be depleted.
The small rectangular bar positioned below the main gauge on the Action Gauge works as a gauge in the Xbox Live Arcade demo of Sonic the Hedgehog (2006), though it does not work perfectly. The Level Indicator also works for Sonic, but is always at the first level, unlike in the final version of the game.
According to the instruction manual of Sonic the Hedgehog (2006), the Custom Actions should also consume the Action Gauge's energy when used. However, this does not happen in gameplay.
Digging into the game's files, however, reveals that they are still supposed to be tied to the Action Gauge, but are incorrectly decreasing a non-existing and probably misnamed variable from the real one.
↑Sonic Team, Blindlight (24 November 2006). Sonic the Hedgehog. Xbox 360. Sega. Area/Level: Mephiles Phase 2. "Rouge the Bat: You'll have to defeat that big one if you want to build up your Chaos Gauge."
↑Sonic Team, Blindlight (24 November 2006). Sonic the Hedgehog. Xbox 360/PlayStation 3. Sega. Area/Level: Solaris. "Knuckles the Echidna: Use the to attack with your abilities! Use the trigger to use your Super Gauge!"