Described by several commentators as an action-adventure game,[2][3] Shadow of the Colossus takes place from a third-person perspective in a three-dimensional (3D) graphical environment and involves combat-based gameplay sequences, as well as platforming and puzzle game elements.[4] The game's environment is largely presented as a seamless open world.[5] Progression through Shadow of the Colossus occurs in cycles. Beginning at a central point in an expansive landscape, the player seeks out and defeats a colossus, and is then returned to the central point to repeat the process.[2] To find each colossus, Wander may raise his sword while in a sunlit area to reflect beams of light, which will converge when the sword is pointed in the right direction of the next encounter.[6] The player's journey to a colossus seldom follows a direct route: stretches of varied terrain often require that a detour be taken along the way. Most colossi are situated in remote areas, such as atop cliffs or within ancient structures.[2][7]Once a colossus is found, the player must discover its weaknesses to defeat it. Each colossus dwells in a unique lair, and in most encounters the player must use some aspects of the current battlefield to advantage, a necessity that becomes more pronounced as the game progresses.[9] The first two battles take place on simple, vast, flat areas of land, wherein the player's only goal is to discover how to scale the colossi and attack their weak points.[6][9] However, the majority of the following fourteen battles require that the player make use of the surrounding environment.[10][11]Every colossus has at least one weak point, symbolized by a glowing sigil[12] that can be illuminated and identified by the sword's reflected light.[6][13] Each colossus has areas covered with fur or protruding ledges, which Wander may use to grip and scale the colossus while it thrashes about in an attempt to dislodge him.[2] Wander has a limited stamina gauge that decreases as he hangs onto the colossus; the player thus must act quickly when they scale the creature.[4] Aside from the colossi, who are the only enemies of the game, the environment is inhabited by natural animals. Only one species, however, has an effect on gameplay: eating the tail of a certain kind of lizard increases Wander's stamina gauge. Likewise, the player may find fruit that increases Wander's maximum health.[14]Wander's horse, Agro,[15] plays a large role in the game. Aside from its capacity as a means of transportation, Agro enables the player to fight from horseback, a critical avenue to defeating some of the colossi.[16] However, the game contains many environments that players cannot traverse by horse, and colossi are often found in areas within deep water or beyond large obstacles that must be scaled. Agro cannot travel beyond these, and when separated from Wander by such obstacles, cannot participate in the following battle.[6] While throughout the game, Wander's equipment consists of only a sword and a bow with arrows,[17] in subsequent playthroughs players may access bonus weapons and in-game features after finishing optional Time Attack trials, which allow the battles with the colossi to be replayed with a restricted time limit.[14]