de Blob 2 's story begins with the city of 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 working for the evil corporation from previous games, The INKT Corporation. With this success, he begins to drain colour from the cities and their 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. His mission is 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 significantly from the original console version. The game is now available on multiple platforms, resulting in a more standardized control scheme. Blob's ability to change colours remains, allowing him to absorb paint and transform into different forms. This leads to a platforming and sliding style gameplay experience as he paints the world with various colours. A competitive multiplayer mode allows up to two players to compete against each other to paint the world quickest and accrue points.
Compared to the previous title, de Blob 2 features more types of enemies, power-ups, and a higher resolution. Blob has a new dash attack that can be used to kill enemies and break through obstacles, but this comes at the cost of paint points. Upgrades can be purchased using inspiration points, including better defence and the ability to carry more paint. Power-ups include transforming into a wrecking ball, providing unlimited paint, or a hazmat suite, as well as turning Blob into a black hole. The game places more emphasis on platforming elements, with Blob able to enter buildings that change the gameplay from 3D to 2D. Different platforms must be completed before a building is fully taken.