I like the idea. I think the spawn time for the second head to appear is too long though. Surviving a minute with one guy is very easy. He needs to appear sooner, and maybe you should start with two.
I like the art style, it's simplistic yet works. The collision of objects has a neat particle effect. You've got a lot of nice game juice on the visuals, the bounciness of menus and what not.
But it needs more game juice! Some sounds and maybe music would make the experience a lot more enjoyable. Silently clicking on the guy for one minute got tedious.