Reduced price for £11.99 @ PlayStation Store between 23/12/2016 to 20/01/2017. Seems to be the cheapest it's ever been (disk or digital) I believe.
"When a mystical phenomenon appears, drawing the world’s finest young Shinobi into a parallel dimension, everything they know about life and death turns upside down. Taken to a strange world resembling a warm summer island, the girls find themselves tested both physically and mentally as they're pushed to their limits to prepare for the unforeseen challenges ahead.
Featuring the biggest roster of fighters to date, SENRAN KAGURA ESTIVAL VERSUS is overflowing with explosive ninja moves, outrageous clothes-clearing combos and a scintillating storyline. All previous favourites return, with new moves and upgraded skills along with a host of new characters, further expanding the roster with new challenges and techniques to master.
As well as the plethora of single player content, SENRAN KAGURA ESTIVAL VERSUS also features online multiplayer matches, allowing up to 10 PlayStation®4 players to battle it out at once in game modes such as Shinobi Deathmatch, Understorm & Capture the Bra."
Also available during this time period from the PlayStation Store:
Senran Kagura Estival Versus [PS Vita] - £10.99
Senran Kagura Shinovi Versus [PS Vita] - £7.99
Senran Kagura Bon Appétit! [PS Vita] - £5.79