City Blocks is a strategic puzzle game where the objective is to connect three buildings of the same type to construct a new, larger building. The game allows for continued expansion as long as there is available space, but as the city grows, the challenge increases. Players are provided with a Joker that can be utilized to acquire a specific building type needed to combine with two others, thus freeing up space. The larger the city, the higher the player's score, encouraging a focus on ambitious growth.