It's...

The Idea was great but the execution was not. The game just felt like it was purely luck and to most gamers that means the whole skill of it gets thrown away too. So in that, it was quite difficult to advance to higher levels.
Maybe a time limit with time bonuses every time you get 5 black squares in a row?

I love games like these. They really make you think, and force you to invoke a LOT of perception and reading your opponent's intentions.

Gets pretty tough as time goes on, too. I can't really tell you how to make it better, because to me it's perfect as is. Well done.

5/5