A short and sweet little game you have made! You already did a little bit to animate the hammer and I think you could improve it by making the animation a bit less linear (eg speeding up and suddenly stopping). Another thing I feel would add to the game is some kind of score counter so that you can try and compete with yourself or others. A weird thing I noticed while playing is that you can see the hammer through the cookie and that looks a bit strange especially when they are not aligned perfectly. Great game!