The game Hatris is set in a hat factory where hats are dropped down from a conveyor belt two at a time and must be stacked on one of six mannequin heads. The goal is to stack five hats of the same kind on top of each other, which rewards the player with a cash bonus.
The game gets progressively harder as the player progresses through levels, with more types of hats appearing and increasing difficulty. If one of the stacks of hats reaches the top of the screen, the game ends. In addition to the main gameplay, some versions of Hatris feature an aid system that allows players to receive temporary assistance from avatars of Alexey Pajhitnov or Vladimir Pokhilko.
The Game Boy version of Hatris features a unique gameplay mechanic where hats are stacked on mannequin heads, while other versions have slight variations. The NES and Famicom versions offer different features, such as the aid system in the NES version and a sale screen in the Famicom version.