Unlike its predecessors, which have MMORPG-like gameplay,[5]Lost Song is labeled as an action game instead of a role-playing game.[6] It is the first game in the series that allows one to play as characters besides protagonist Kirito; there are 19 characters available, though two are only attainable through downloadable content.[7] Additionally, players can create their own character to use in the game's story mode. Regardless of which character is being used, the story will progress as if the player is Kirito.[8]Each character can wield three types of weapons—for instance, Kirito can dual-wield or use a one- or two-handed sword—and weapons have skills that can be trained to unlock new abilities.[9]
While in battle, a party consists of three members: the player and two player-selected characters. Fighting is performed on the ground and in the air, with the latter allowing the player to move freely, although players cannot fly in dungeons[10] and are restricted to an altitude limit during the early portion of the story.[11] Auto-attacking, which is disabled during flight, enables other party members to automatically attack an enemy in close enough proximity without command from the player. In combat, the player can assign magic spells and attacks for the other two party members to use.[9] The type of spells available depends on the race of the character; for example, Salamanders use fire-based spells, while the sylph use wind magic. In a party, the character that the player assigns to perform magic is not targeted by enemies.[12] During combat, there is a "Union" gauge which, when filled, allows players to perform the "switch attack", where one character attacks first and a party member immediately follows with a second attack.[9]
The game has multiplayer, allowing players to engage in player versus player (PvP) duels.[13] Online capability is also available, with a lobby featuring up to 16 players who can be split into four-person parties to complete quests,[14] such as fighting stronger versions of bosses found in single-player.[15] Four-player groups can also participate in PvP as 4v4 battles.[16]
