Birth by Sleep is an action roleplaying game. This game allows players to customize their "deck" by choosing which techniques and abilities to display.
Another new gameplay aspect is the Command System; when the command gauge is filled and requirements have been fulfilled, the Command Style of the character will change. When the gauge fills up and the requirements have been fulfilled for the second time, the character will change to an even higher level Command Style.
A new feature of the game is the Command Board, which appears whenever the player completes a world, and can be accessed from save points and the world map once unlocked. Each world has its own unique Command Board with its own tricks and mechanisms. The Command Board plays like a regular board game where a dice is thrown and the player moves, each space having its own unique effect on the player. Various Disney characters from throughout the game also appear on their respective Command Board to either aid or hinder the player. Special panels in the board game can trigger "special events" when landed on by the player.
The game does not utilize a Magic Points (MP) system for spells or magic casting, unlike in previous games in the series. Instead it uses a new system known as "Focus" which is displayed in a gauge on the interface, involving targeting spells using what is known as the "ShotLock Mode". It also involves the characters casting spells in a first person mode, where each character is able to cast their own unique magic attacks.
Another new aspect of the game is the Dimension Link (D-Link) which can be used to summon allies to lend their power to aid the player from different worlds. Companions such as Experiment 626 who have been left behind in previous worlds can be called upon once again to temporarily aid the player in his or her, by providing them with an entirely new range of attacks in their command decks replacing the usual ones. At the end, a new powerful finishing move is activated to take out enemies. Each ally used will have a unique set of attacks and finishing move. Each finishing move has two levels which can render a finishing move more powerful than before, similar to that of the Command System. The D-Link can be activated by pressing 
to access the D-Link menu, followed by selecting the chosen ally namely, Experiment 626, Aqua, Ventus, Terra, and several others.