Yakuza: Dead Souls

Endless Subterranea is only available in Premium Adventure. You need to speak with Bob A with any of the characters to start this. This is similar to the Subterranea Missions where you need to make your way through random levels to find the ladder that leads downwards to the next level. I prefer to use Akiyama with his Elise twin handguns due to their decent damage, large clip size and infinite ammo supply. Equip your best armor and defense accessories, bring along lots of Healing Items (6-8 Toughness Infinity), your strongest Shotgun for clearing Aggros and groups of enemies if they surround you and 2-3 Batteries to recharge your LED Torchlight, because there is no Underground Vendor this time around unlike the Subterranea Missions from Kine.

Whenever you see a long rectangular hallway (that looks like an 8 on the map) or one of the big squarish rooms (that usually has a mounted weapon in it), head in that direction because the ladder leading downstairs always that way. It takes about 1.5hrs to clear 50 levels. The trophy unlocks when you've reached at the 51st floor.