I don't play clickers much, but I think they're generally supposed to do more to trigger the feelings of progress and accomplishment. I think if you had a particle effect on each click (nothing fancy, just like an array of positions, speeds and sizes to apply to manually drawn instances a star sprite with random starting values and some formula for the type of movement) and a bar under each of the options for what to buy that fills up to reach the amount needed to buy it, it'd work better. An extra particle effect on actually buying something would help too.