This guide will show you how to obtain the conclusion, the best weapon in the game.
What You Need to Do
Progress the story until you obtain the red diamond key and the green triangle key.
Go all the way back to studio 4, go to the room where you obtain the blue circle key and the wrench.
Go through the door with the red diamond symbol on it.
Turn right, and go through the first door on the left.
Go to the safe and open it, the combination is 7 12 4 (clockwise, counterclockwise, clockwise)
Take the fuse inside the safe,
Go back the the fusebox in the sewers, at this point in the game you will need to use the elevator in the public park to reach it, as the tunnel is blocked off and the boats are gone.
Insert the fuses in this order from left to right, spade, star, diamond, heart. this will unlock the other door.
Go through the next door to go to Stage 5.
On the cave to the right when you walk in, there is a treasure chest which contains the conclusion, but you will need to find 3 gemstones to open it, a red one, a blue one, and a green one.
Exit the cave and turn right, go down the path, there will be two pirate puppets you will need to deal with.
Go over the boardwalk and keep walking, the green gem is at the end of the path.
Go back and go up the stairs, cross the bridge to find the red gem on a sword.
Go back to the cave where the chest is, the blue gem is sitting on top of a barrel next to the chest.
Insert the gems into the chest.
Take your new weapon. along with 2 tokens.
Enjoy your new weapon!