The gameplay is generally similar to Sticker Star's in that Paper Mario interacts with the environment's paper-like qualities to progress. This entry includes a color mechanic where Paper Mario swings his hammer to color a spot.
This rewards the player with coins and sometimes cards. It can revive decolored characters as well. Filling in all the spots helps with completion
The combat is also similar to Sticker Star in that to attack the player selects a card. The player taps the card to color it which powers it up. Sending an uncolored card is much weaker but, will work. After the attack is started, action commands for each attack can take place which will improve the attack's effect.
The amount of paint left on the enemy's sprite is how much health they have while Mario still has numbers. Defeating enemies give hammer points, which upgrades the amount of paint that can be stored.
The player can hold up 100 cards including Thing Cards that are real objects that are much more powerful than normal cards. Thing cards are almost necessary to defeat the bosses, be it a Fire Extinquisher to put out Morton's hammer or a Bone to get rid of Iggy's charriots.
There are also enemy cards that summon an enemy to fight for you and take a hit. For all the different cards in the game, see this page:
Players can donate battle cards to the museum hidden at the dojo in Port Prisma. The more cards donated, more art pieces will be unlocked. The music from 100%ing levels will also be here
The game starts when Mario gets a letter, turning out to be a decolored Toad. He and Princess Peach head to Prism Island to discover the cause. As he arrives in Port Prisma, he discovers Huey, a paint can and a Toad getting attacked by a Slurp Guy. In the meanwhile, Peach gets kidnapped by Bowser and Mario must collect the Big Paint Stars to restore Prism Island to its original state.