Legitimate copies are sold through Steam , GOG.com (where it is DRM-free), and various console stores (PS4, Xbox One, Wii U).
The game has previously been offered as a free title for PlayStation Plus members (e.g., September 2018). Q.U.B.E: Director’s Cut Free Download
The Director’s Cut is the definitive version of the 2011 original, adding several significant updates: Legitimate copies are sold through Steam , GOG