It's quite a great idea, but I feel like you could explain it better. I struggled looking for what I was supposed to do, so I ended up focusing on the only thing I got which was trying to make towers going from 6 to 1. I am curious as to what kind of score you're able to rack up as the developer, to see if I did well or if I just had the impression to do well (I got something juste over 12000 points.)
I guess it's because of time but what your game lacks the most for me is the finishing touch: music, effects, a tutorial maybe (I rarely have time to implement them myself :( )
I think it is a very smart and cool concept, I can see it as a fully fledged game.