Test your timing and focus with Rainbow Stacker, a gorgeous reaction game in which your objective is to build a beautiful rainbow tower. Stack up the tiles to create a tall tower. Each tile is a new color, shifting along a rainbow gradient. Stop the sliding tiles at the right moment so that each tile aligns perfectly with the last tile. If you miss by a little bit, the tile will shrink reducing the surface your have to work with. How high can you stack your tower?