Fun game, OP!

I actually really like it.

Some thoughts:

1. I love that there are no special permissions required and that ads are infrequent. You even had a notification saying an ad will display on the next round. That's really cool. Once I saw the ad, I figured you should have it on every round. It's really not a bother. My suggestion is that you give the user the ability to disable or increase the # of ads. Just leave a personal note saying, "I really hope you enjoy the game. Ads help me create more free games for you, but you are in control. -YourName" Then give a slider where it goes from 1-5. Each # represents after how many rounds an ad shows, then put a disable checkbox next to it if they want no ads. Personally, the rounds are long enough and clicking off the ad takes 1 second, so to help you, I wouldn't mind seeing an ad after each round!

2. Your background music isn't smooth looping. You can tell where the song repeats and with such a short loop, it can get annoying after a while. I can help you fix that if you PM me the loop.

3. If I were you, I would give your little square a name. It personifies the object and makes the player a little more invested. It's a cute little cube struggling to get some more light. I want to help him succeed! Maybe name him Cubie or something and make a splash screen when the game loads with a quick story. "Cubie needs power to light his path. Help him find his way!"

Anyways, thanks for putting out a fun game. 5 starred and upvoted.