Are you shitting me? All this grinding towards being able to break the last material and then there's NOTHING?
Not even a popup saying "Conglaturations! You have completed a great game!". No! Instead, the 'next stage' button goes active but is defunct! >:(
For the ultimate Lightshow, you need 71280 coins once you've unlocked all slots. That way, the whole grid can be filled with Level 5 Lightning Rods: http://prntscr.com/ayzgq4
It is? Like, the keys are far apart making it difficult to play? Or are there other issues?