Smile Cube is a matching block puzzle game. It features colorful, smiling anthropomorphic cubes in rows on a black-and-gray checkered board. The player must attempt to clear the board of all cubes by selecting two or more adjacent identical ones at a time.
The game consists of four rounds. The player starts by searching for two or more matching cubes positioned in a line in a row or column or as a section of cubes that form an L, a square or some other shape within several rows and columns. When the player selects matching cubes, the game removes the pieces from the board, and the remaining ones fill the empty areas by dropping or sliding into place.
If the player fails to clear the board, the remaining blocks turn into unhappy, frowning gray stones. The only way for the player to remove the stones is by removing adjacent smile cubes during the next round.
Smile Cube offers two boosters. The player can take out a large section of mixed-color cubes with a cube labeled with a star that doubles as a bomb. The player can also use a button at the bottom-right corner to remove all cubes of the same type as a selected cube. That said, the player must watch an ad to use this tool.
The player receives points for their efforts. They receive bonus points when they use a bomb or clear the entire board. Once the game ends, their goal is to restart and attempt to beat their previous score.