Shadow the Hedgehog is a platform game that incorporates elements of action-adventure gameplay. Like previous games in the Sonic series, basic gameplay involves running quickly, collecting rings, and destroying enemies.[1][2] Shadow collects rings as a form of health; when he is attacked by an enemy, ten of his rings bounce away from him in all directions. If he is hit by an enemy while not having any rings, he loses a life.[3] Each level is completed by undertaking a mission, and each mission is labeled "Hero," "Dark," or "Normal".[4] The "Hero" missions involve completing tasks for the Sonic series' heroic characters, or Doctor Eggman on one occasion,[5] and the "Dark" missions involve completing tasks for the Black Arms or Doctor Eggman. The "Normal" missions involve reaching the Chaos Emerald or goal at the end of the level.[4] Examples of non-neutral mission objectives include killing all enemies in the levels, destroying an aircraft flying to the end of the level, or activating or destroying objects in the level.[6] All enemies attack Shadow regardless of the mission chosen.[2][3] The mission types selected affect the plot, the levels played, and the ending received out of ten possibilities.[4][7] Each level features cutscenes that advance the story, and several levels also feature boss battles.[8] There are 326 possible paths to take in Shadow the Hedgehog, and each pathway is individually named.[9]
Shadow uses a submachine gun to shoot a G.U.N. soldier. The game's mature themes and addition of guns were two major areas of criticism.
New gameplay features distinguish Shadow the Hedgehog from previous Sonic games. For example, Shadow can use guns to combat enemies, adding an element of third-person shooter gameplay.[3] Parts of the scenery, such as traffic signs, can also be used as weapons.[4] Another new feature is the ability to drive vehicles, such as motorcycles and alien aircraft.[1][3] Although Shadow can outrun the game's vehicles, the latter have unique capabilities, such as crushing enemies and traversing otherwise impassible acid-covered areas.[8]
As in most Sonic series games, the Chaos Emeralds play a major role; they help Shadow remember his past[10]and allow him to perform Chaos Control and Chaos Blast. Chaos Control allows Shadow to move more quickly in levels and slows time in boss battles, and Chaos Blast creates an explosion that destroys or severely damages all nearby enemies. Shadow can perform Chaos Control after the player fills the Hero Gauge by defeating Black Arms soldiers, and he can perform Chaos Blast after filling the Dark Gauge by defeating G.U.N. soldiers.[1]
The game includes a two-player mode[11] that retains the single-player mechanics but is set in one of three specially designed stages and uses a vertically split screen to separate each player's view. Each player chooses one of the available characters—Shadow, two metallic versions of him, and palette-swapped variants of each. The combatants attack each other and steal each other's rings until all but one are eliminated. Additionally, in single-player mode, a second player may take control of Shadow's sidekick character in some stages.[8]
