Entertaining to watch, painful to play
This is one of those games that I would label as "wrist killer", it's a great concept but it doesn't actually keep the player intrigued. I also found myself click multiple times on the same block because (for some reason) my clicks were not going through. If there was a suggestion that I would give it would be that your click (And I guess the graphic that comes from clicking) should be some sort of AoE (Area of Effect). At least that way when you're facing large numbers of blocks you're able to defend a lot easier.
I give it a 7/10 for concept, but for actual game play I wouldn't suggest a friend to try it.