Bioshock U also known as Bioshock 4 is the last instalment in the Bioshock Series continuing the ending of infinite and now taking place under the earth itself. It's element is earth or rock. It still feels like a Bioshock Game only censored in some regions.
You play as Alex a new main character as you explore and kill and discover items in the mysterious underground city of Lomanious. You mainly kill splicers which have a new kind called drill splicers which have drills forcefully attached to their body,you kill them. You also look for food or drink to heal and audio logs to discover the backstory. It also utilises the touch screen for inventory for consumables like food or drinks and weapons.
The game takes place in the subterranean city beneath the earth of Luminous. The city is located beneath Detroit and was originally going to be used as a bunker of sorts in case the city was nuked but that didn't happen so instead philanthropist and multi-millionaire Jerry Vigor buys it and performs horrific experiments on the remaining splicers before going insane.