If you already have Attack On Titan 2, the expansion is available by itself. Attack On Titan 2: Final Battle is a re-release of Omega Force's Attack On Titan 2, bundled with a new expansion covering everything in the anime series so far, adding some interesting new modes besides.
While the manga may have fallen down a dark and nationalist hole, Attack On Titan's escalating human-on-giant war makes for some fun games.