Underflow

Floor 1 East: Follow the only path available. At a junction, head down to find 1000 pg in a chest. Return and head left and up. At the next junction, head left for the stairs. Before proceeding, head right from the junction to find chests containing a Bomb Fragment and Bomb Arm.

Floor 2 East: Make your way down the fiery tunnel to a junction. Continue down. At the next junction, turn right to find a chest with 2000 pg. Return to the first junction, turn left, and stop before the next junction. Follow the tunnel left to find a chest with a Safety Ring. Return and follow the path down to find the stairs.

Floor 3: The pathway may crumble; find your way around. Follow the path anti-clockwise from the entrance, passing three junctions, to find an X-Potion in a chest at the end. Return to the last junction passed and head left. Follow the path clockwise past a crossroads to the top-left corner junction. Head all the way right to find chests containing a Flame Charm and Turbo Ether. Take the nearby stairs down.

Floor 2 West: From the entrance, head down at the first junction to find a Diamond Staff in a chest. Return to the entrance, head left, and follow the path to the southern part of the floor. Head right and turn at the first junction to find a Flare Hatchet. Head left and turn at the next junction, then follow the winding path to pick up a Gale Bow. Continue left to find the stairs.

Floor 1 West: Make your way left towards the orange exclamation mark for an event. After the event, you'll be on the other side of the floor. An exit in the bottom-right corner leads back to the first area. Head north to the next orange exclamation mark, which is the entrance to the Temple of Fire.