Guilty Gear XX Λ Core Plus, with Λ standing for "Accent", is the fourth update to Guilty Gear XX following Guilty Gear XX Λ Core, and the overall eighteenth installment of the Guilty Gear series. No changes to the battle system were made, but new features were added including a new Story Mode that continues the story from XX.
Following the events of Guilty Gear XX, many a character enters into direct conflict with the Post-War Administration Bureau and the director of one of its branches, the amoral scientist Crow, who hopes to perfect his Imitation Series-version of Justice.
- Kliff Undersn and Justice, with appropriate changes and additions made for the game, return.
- Λ Core Plus features a new, fully-voiced Story Mode, continuing from the prior XX titles. While it has a total of 350 scenarios, most characters now only have two story paths/endings each, but no longer require as many other prior story mode paths to be completed first for access.
- Mission Mode is reinstated, but with only 25 challenges.
- Survival Mode is re-hauled with various level-up features.
- Gallery Mode contains new illustrations.
- There are several bug fixes, rebalances, and tune ups from the previous version.
- The PlayStation Portable version includes 3-on-3 tag matches.
- Almost all stages from Guilty Gear XX Slash are unlockable by clearing certain tasks in the game, namely by clearing the characters' respective story modes for their stages. It is also possible to select the ♯Reload versions of said stages by selecting them with the Start button instead.
- The game's re-release by Asksys Games in 2012 on Xbox Live Arcade and PlayStation Network, features online play by addind Player Match and Rank Match Modes.
- This game along side its updated version Λ Core Plus R, are the only entries in the series to receive an ESRB rating of Mature on specific versions; in this case in its Xbox 360 (via Xbox Live Arcade), and PlayStation 3 (via PlayStation Network) releases.