Puyo Puyo!! 20th Anniversary Cheats

Unlock all characters, cutscenes, and 9999 shop points
To unlock all characters, all cutscenes in the gallery, and obtain 9999 points for the shop enter the follow commands at the title screen. You will hear Carbuncle's voice if it was done correctly. This code does not unlock the items found in the shop but you can enter this code multiple times to regain all points spent at the shop.

Unlock all characters, cutscenes, and 9999 shop points: At the title screen hold L+R and then press up, down, right, left, X, B, Y, A

Unlock Hard AIs, Endless Mode dropsets etc.
Enter these codes at the specified part of the game to get the desired effect.

Choose Random Mode: Press X while in a mode select menu.
Harder CPU in Battles: Hold Select while selecting the CPU character (in Endless modes, hold select while selecting your character)
Instant Win: Press L + R + X + B + Y + A during a match. Note that you will only earn 1 point at the end of the match when you use this cheat (as if you lost).
Set Player as CPU: Hold Select while selecting the difficulty during the start of the match.
Show Nuisance Multiplier: Press Select during a match. (Pressing Select again hides it.)
Use Classic Voice Pattern: Hold Select while selecting a mode. This only works for Arle, Schezo, Rulue, Satan, Carbuncle, Suketoudara, Witch, and Draco for Puyo Puyo, Puyo Puyo
Use Dropsets in Endless Modes: Hold Select while selecting your character.

Hidden modes
There are five gameplay modes that are hidden which includes: Non-Stop Fever, Excavation, Giant Puyo, Ice block, and spinner. To unlock these modes keep purchasing the item in the fourth tab of the shop until you unlock one of these modes. You must unlock all five individually this way.