I like the idea of this game, trying to find the correct voltage through trial and error. However when I got to the third one the meter was already filled and my input didn't do anything. I think there may be a glitch there.
For other ways to improve the game, I think there's not much of a consequence for failing, you keep trying until you inevitably get it right. Maybe if you get it wrong too many times the battery blows up or something?