de Blob 2's story starts off with the central location, Prisma City, and its upcoming general election following the events of the first game. A mysterious priest called Papa Blanc deviously plans to rig the elections in order to gain power. Once successful, it is revealed that he is in fact working for the evil corporation from previous games, The INKT Corporation. With this success, he begins to drain colour from the cities as well as the inhabitants, in order to uniform the world in a total lack of colour and uniqueness. It is up to our hero Blob and the members of the Colour Underground to restore the city to its vibrant former glory. Blob frees the lands one by one, rescuing and reuniting friends along the way. It is his mission to restore the world to colour, free the population, and stop the mysterious INKT Corporation once again.
The gameplay in de Blob 2 has been updated from the original console version, with a focus on standardised console controls. The same colour-changing mechanics return, allowing Blob to absorb paint colours and change his appearance accordingly. Players must navigate through levels, painting the world with various colours while avoiding enemies. A new multiplayer mode allows up to two Blobs to compete against each other, racing to paint the world in their respective colours. Co-op play is also available, with the character Pinky providing assistance.
The game features a wider range of enemies, power-ups, and challenges compared to its predecessor. Blob has gained a new dash attack, which can be used to kill enemies and break through obstacles. Upgrades can be purchased using inspiration points, such as improved defence or increased paint capacity. The power-ups include items like a wrecking ball, unlimited paint, or a hazmat suit. The game also places more emphasis on platforming, with Blob able to enter buildings and complete 2D challenges before fully taking them over.