btw is a puzzle game played on a grid with an entrance, an exit black dots, white dots and color switching tiles.
The goal is to draw a path on the grid from the entrance to the exit, covering all tiles with dots. The trick is the path you draw must be of the color matching the dot's. So you need to use the special tiles to change the color of your path (from black to white or from white to black).
The game contains 88 levels.