The animation of the scale is very good and since its the heart of the gameplay, I think you nailed it.
The dialogues are perfect. Some of them are fun, some of them are absurd, most of them are serious. The balance is good.
I think it's a pretty slow game, kind of relaxing. I wished you could play it mouse-only without having to reach for the spacebar between every customer.
I'm glad it's sometimes very hard to find the real weight of an item and sometimes pretty easy. Great job !