The following is paraphrased from Sonic Angel Knight's guide to unlocking content quickly in Puyo Puyo Tetris. (Refer to the linked guide for more detailed info)
If you want to skip grinding for credits, you can unlock everything in the game with a cheat code. (This includes content unlocked from Adventure Mode)
Method 1 - Cheat Code
To permanently unlock all characters, skins, voice packs, and music, enter the following cheat code on the title screen. (A jingle will play if done correctly)
- Switch/Wii U/3DS: Hold L and R, then press Up, Down, Right, Left, X, B, Y, Y.
- PS4/PS3: Hold L1 and R1, press Up, Down, Right, Left, Triangle, Circle, Square, Square.
Xbox One/PC*: Hold LB and RB then press Up, Down, Right, Left, Y, B, X, X.
*Assumes you are using an Xbox controller for PC.
Method 2 - Grinding Credits
If want to grind out credits instead, you can use the following exploit:
- Go to the arcade mode and select Big Bang Mode > Battle > One CPU
- On the character select screen, press start to skip it. (It auto selects current highlighted characters for all)
- You should be on the custom options screen, this is the screen where you set up how you will play the mode. Simply hold both shoulder
buttons (L1/RB/R & R1/RB/R) and select play.
- Notice how you don't have control over your chosen character, it should be playing by itself at a very intense rate while the opponent
is very tame. Simply wait for the battle to be over and see see the
results. (Your character will always win which is what you want)
- On the results screen, you should notice you earned credits based on performance. Baseline, Chains, and all clears will total how much
credits you earn, because of the performance being random, this will
fluctuate. You can simply hit retry and watch it all over again.
- After some time pass doing this method, you should have accumulated a lot in a short time. Please remember the maximum credits you can
hold at once is 9999, so make sure to spend them before repeating the
method again to get more. (You should need at least 3 trips to the
store at max credit score.