To view the best players screen (which is firstly seen on completion of the game), press B + Start at the title screen.
At the title screen, press and hold Down + Right + Start to view the demonstration.
To instantly switch from your Alt. Knife to the weapon currently selected in the weapons menu and vice versa without needing to open the weapons menu up, hold Mode and press B. Please note that this command requires a 6-button controller.
These codes require a six button controller. Before proceeding, make sure that on the Diary screen with the 4 save slots it highlights an empty save slot by default. On the title screen, hold the buttons listed in the cheat and keep them held as you press Start twice (once to open the Diary screen, the second to begin a new game) A sound effect will confirm success. For the area select and dialog viewer code, hold the MODE button as you open the save screen during gameplay to access the area list. To access the dialog viewer, hold X and Z, and then press A or C to close the menu you just opened. With X and Z still held, walk up to a NPC and press B to talk. The game will now cycle through the story text.
NOTE: This will only work after you have the Warp Device.
Go to the seashore on the lower west side of the map. Use Shade's Doppelganger to locate the invisible silver crack (the warp), then use your Warp Device to open up the warp.
You'll then be transported to a secret island located on upper west side of the map.