It is a color 2D puzzle, the target is to collect the pieces of the same color into blocks of 2 x 2 or 3x3 or 4x4, depending on chosen cross size.
You can rotate coloured cubics up-down or left-right, so transferring it to neighbour blocks. All the colors are connected to each other, and when you rotate a line, a whole near block is rotated at once, this makes it tricky to solve.
Performance increase.