Catastic!
It's a good written game. Seriously don't drag, just click, that's the main point. And, there are only 20 levels, how come someone said hitting 30+ something??
Take good use of space. It will definitely save you life. Think before striking anything.
As for the boss, don't hit him directly -- it will strike all your amor back. The only way to destroy him is to hit back the rocks he releases.