It took me a little while to work out exactly how the switches worked. I think because the light goes into them even on sides where there's no line. So the L piece outputs light where the lines are, which is clear, but it takes in light where there's nothing. I think if there was a little half circle or triangle of light in the tile reaching the centre, or something like that, it would be a bit easier to work out.
But that notwithstanding, I think this is a great game. I love this kind of thing, and this is a snappy & fun implementation. I really like the background music too. I would prefer if the pixel art was slightly higher res & less abstract, but it's nice and clear as is.
Good job (y)