Coloris sees players eliminating colored squares by altering the color of other squares to make them the same color as the squares nearby.
The game features two different game modes: clear mode and score mode. In clear mode the player must eliminate a certain number of squares (depending on the difficulty level) before moving on to the next level. In score mode the player must eliminate squares to achieve a high score.
Part of the Japanese-only Bit Generations series.
Source: Wikipedia, "Bit Generations", available under the CC-BY-SA License.