Soulcalibur IV features Story, Arcade, Training, and Museum modes. A new mode, Tower of Lost Souls, requires players to win battles to gain rewards.[3] The game runs in HD resolution with 5.1 channel surround sound on both platforms.
The Character Creation mode from Soulcalibur III returns in Soulcalibur IV. However, instead of including original weapon styles for use with certain classes of fighters, Soulcalibur IV allows players to choose which character from the series they would like their created character to mimic. This differs from Soulcalibur III, which featured many unique styles such as "Grieve Edge". The styles of Algol, the bonus characters, and the Star Wars guest characters cannot be used by player-created characters. A wide array of new equipment pieces are available for use in Soulcalibur IV's Character Creation mode, and new options include a broader range of character voices and the ability to adjust their pitch. Players may also modify a character's general physique and muscularity.
Additionally, equipped items now affect a character's statistics. Armor, weapons, and accessories may increase health, attack, or defense; they may also grant skill points that allow the character to equip special traits affecting playstyle.[4] These traits may include automatically triggered guard impacts, the ability to inflict damage on a blocking opponent, or even a statistic increase based on parameters such as an opponent's alignment or gender. Standard characters can also be modified in this manner, albeit only modestly, allowing custom costumes and skill sets to be used in Special VS. mode. Custom characters may still be utilized in Standard VS. mode but without any special abilities gained through equipment or weapon choice. One profile is permitted for Offline VS. mode, meaning that only one profile's created characters can be loaded at any given time.
Multi-fighter battles in Soulcalibur IV employ a different structure from its predecessors, known as Active Matching Battle (AMB). Similar to the tag system of games such as The King of Fighters 2003, the AMB system allows players to switch to other members of their fighter party mid-battle. Instead of starting a new round for each defeated opponent, new opponents enter the battle immediately after a K.O., with the exception of certain combatants. Matches utilizing the AMB system only appear in the Story and Tower of Lost Souls modes.
Soulcalibur IV introduces an all-new Critical Finish system. Next to a player's health meter is a colored gem known as the Soul Gauge. The gem changes color when the player blocks an attack or has their own attack blocked by a Guard Impact. The color transitions from blue to green, then to red, and eventually flashes red. The player's Soul Gauge regenerates if they successfully hit the opponent with an attack, guard, or otherwise. If a character manages to deplete the opponent's Soul Gauge, the enemy suffers a piece of armor destruction (characters now display permanent visual damage, such as broken and torn clothing) and experiences a brief stun during which the character can execute a powerful Critical Finish move by pressing all four face buttons simultaneously. Each character has a unique Critical Finish move. Namco developed the Soul Gauge to mitigate the advantages of constant guarding, thus enhancing the game's tempo and making matches more offensive.[5]
The Star Wars guest characters, Darth Vader, Yoda, and the Apprentice, utilize unique attacks powered by the Force. Darth Vader can employ Force-based blasts, punches, and chokes; Yoda can use the Force to propel himself into the air for intricate aerial attacks; and finally, the Apprentice is capable of wielding Force lightning and other dark-side abilities. These moves consume a special Force Meter, which gradually recharges when not in use. If the Force Meter is depleted, the player momentarily loses control of the character.
For the first time in the series, Soulcalibur IV includes an online multiplayer option. The versus modes available in online battles are Standard VS (for classic matches) and Special VS (for customized characters).[3] Created characters are playable in the online multiplayer mode.[6] A player's wins and losses are recorded and used to establish a ranking level that reflects their online skill.[3]