Vessel is a game about an engineer who operates machines in a heavily industrialized steampunk world. The player assumes the role of Arkwright, a genius scientist who invented a new type of automaton called Fluro. The Fluros are amorphous creatures that can be made of any type of liquid and perform tasks for people. One day, the Fluros mutated and went out of control, ruining most of the world’s machines. Arkwright has to find the cause of the malfunction and restore control over the Fluros.
The gameplay consists of solving physics-based puzzles and manipulating the ridiculously complex machinery in a 2.5D environment. Arkwright jumps the platforms and pushes buttons to activate machines in a certain way. He can also use devices called Seeds to create new Fluros out of the liquids found on the levels, including lava. The Fluros, in turn, can be manipulated to perform helpful actions, such as to pull switches that are inaccessible for Arkwright. The liquid is the central element of the game, and a special graphics engine was made to animate it. The music by the famous DJ Jon Hopkins works as a hint for the player, becoming more complex when he or she does the right actions.