Rather dull.
Murdering Justin Bieber has never been in my top list of things to do. The same goes for his pet beaver. However, I suppose the internet needs a fair share of such games, and you can provide for this quite well. :P
As for the game itself, it's quite a bit boring. You throw stuff at the beaver until he eventually dies. It gets boring after the first two levels, and I can't find myself enjoying it. If I had strong urge to murder Bieber, this wouldn't help. In short...Not fun.