Merge Items is a casual crafting and world-building game that uses merging actions to construct, renovate and upgrade city buildings. The player builds a city from their crafting efforts.
The game gives the player a certain amount of money that they can use to buy the raw materials needed to construct building materials. It also features an idle aspect. Existing buildings auto-generate revenues every few seconds.
Construction of new materials is necessary to create stairwells, red brick walls, windows and other building elements. The player selects a building or construction zone and then uses a button labeled with a hammer to access the merge area. They're then given access to one or more raw material cards edged with blue below nine empty fields and tasks for constructing new materials above the cells. The merge mechanics are similar to the Doodlegod and Little Alchemy games. The player selects a material card to deposit the material on a cell and repeats the process to fill all cells. They then merge identical materials to create new ones.
Merge Items features materials commonly used in construction, such as stone, sand and trees. New construction materials include stone and concrete blocks from stones, wheelbarrows of sand from sand, logs from tree branches, and planks from pallets of logs.