Dark Energy Force Fields

Dark Energy Force Fields, also called Force Fields, are a type of barrier that appear in the PlayStation 2/Wii version of Sonic Unleashed. They serve to halt the player's advances through the nighttime Stages by blocking paths.

Description
The Dark Energy Force Fields are impenetrable barriers made of the stray energies from Dark Gaia. Their appearance is that of a flat surface of purple energy with a black ring, which is adorned with six small spikes at the edges and three circles, on it. When a Dark Energy Force Field appears, it seals up an enclosed space. They only appear in the game's nighttime acts.

In gameplay, once the player advances to a certain point in the act, a Dark Energy Force Field appears and seals up a path that the player has to pass through in order to complete the act. The only way to lower a Dark Energy Force Field is by collecting three Dark Energy Keys that are placed in different locations throughout the act up until the Dark Energy Force Field's location.

For each Dark Energy Key that the player collects, one of the three smallest circles on the Dark Energy Force Field starts to glow purple, until all three keys are collected. Once the player arrives at the Dark Energy Force Field with all three Dark Energy Keys, the force field will dissolve and be lowered, allowing the player to proceed.