Presumably the Pigsy's Perfect 10 add-on is included as part of the Premium Edition. While no concrete date is set, a Namco rep said it was due later this month for PS3 and PC.
While critically lauded, Ninja Theory's Enslaved - which is a re-imagining of the Chinese tale Journey to the West - never managed to secure high game sales.
Namco Bandai confirmed the Premium Edition to Polygon, also revealing a PC version. Steam was found to have 'Enslaved' in its database entries months ago, making a Steam release all but certain.