Knife Smash is an arcade game where you have to throw knives on a rotating surface, trying to avoid hitting those already stuck. When you start playing you will throw knives at a piece of wood, but as you get more points you will throw knives at other surfaces as well.
In each level you will have to play a 'boss fight', where you throw knives at crazy surfaces. In these levels you will have to throw knives at giant tomatoes, sushi, shields, etc. These levels tend to give extra points which you can then use to unlock additional knives.