KQ7, SQ6, PQ4, and LSL6 all share similar music themes. In-game. They're not carbon copies, either. They're slight variations shared between the games. The Polysorbate LX theme from SQ6 is in a scene in the land of Ooga Booga in KQ7 but without the xylophone or glock instrument, whatever it is. A guitar solo from a bar theme in SQ6 is also present note-for-note in a completely different theme from LSL6. It doesn't surprise me that more themes are shared between these later games.