The gameplay and quest structure of Stormblood largely match that of its base game. As with many MMORPGs, players interact with each other in a persistent world that responds to their actions. A dramatic overhaul of the battle system accompanies the level cap increase to level 70.[2] The changes fall into three broad categories.[3] First, battle abilities were redesigned to eliminate redundant actions and improve the flow of combat. Second, a new set of "role actions" ensures that all players can access critical abilities to their role—tank, healer, or damage dealer. Finally, all classes gained a "Job Gauge" that displays all class-relevant information in a more visually distinct way.[3][4] Two new job classes were introduced as well—the katana-wielding Samurai and the versatile Red Mage, both damage-dealing classes.[5] These jobs begin at level 50 with their own storylines connected to the new settings. Unlike Heavensward, they are accessible to any player with a level 50 class, regardless of story progress.[5]
Stormblood introduces a new player versus player (PvP) mode called Rival Wings. Two teams of 24 players face off in goblin-run war games. Points are earned by destroying opposing bases and robot minions. Players are able to call down and pilot giant mecha after achieving certain objectives. The mode has been compared to multiplayer online battle arena (MOBA) games.[6]
In addition to the already-existing normal and Savage difficulty raids, Stormblood adds a third "Ultimate" difficulty that is structured as a single encounter comprised of multiple bosses, which are unlocked by clearing an associated Savage raid tier. These encounters must be cleared in a single attempt with no checkpoints in between bosses, otherwise the party will be sent back to the beginning of the encounter. Players who clear Ultimate raids are rewarded with a single totem they can exchange for a weapon of their choice themed around the raid they cleared. While the weapons are marginally stronger than those obtained from the Savage raid required to unlock the Ultimate raid, they fall outside of standard gear progression and are instead for those seeking a greater challenge. Unlike other raids in the game that can be run "unsynced" with level caps unlocked, Ultimate raids can only be run at the character level and item level caps they were released at, ensuring that their difficulty is largely preserved even as new expansions and patches continue to be released and players get stronger gear from them.[7] With the addition of Stormblood into the Free Trial and Starter Edition of the game in patch 6.5, Free Trial players are barred from participating in Ultimate raids even if they meet the participation requirements, as this would require them to use in-game resources normally unavailable to them.
Finally, a new area called "The Forbidden Land, Eureka" debuted with Patch 4.2. Its gameplay is inspired by "old school" MMORPGs, including Final Fantasy XI and others.[8][4] In Eureka, players must use an elemental wheel to exploit monsters' weaknesses and increase their own Elemental level. Unlike the rest of the game, players lose experience points if defeated and can even "Level Down".[9] Later sections of Eureka permit the use of Logos Actions, which are unique spells and abilities that players craft using materials found in the zone.[10] Eureka culminates in a high tier raid called the Baldesion Arsenal that challenges 56 players to work together to overcome it.[11]