Unofficially? The hacking community has created repackaged PKG files called "Harmony of Despair Complete." However, these are often unsigned. On a standard PS3 (OFW), you cannot run unsigned code. On CFW (Custom Firmware) or HEN, a repackaged can work, but it frequently breaks online multiplayer syncing. For the purest experience, stick to the official, sequential PKG files.
– Retro 8-bit sprite with classic sub-weapon scaling. Castlevania Harmony Of Despair Dlc Pkg
These extra stages expand the game from its original six chapters. Unofficially