Addictive
Definitely has an addictive quality to it. However, I think the appearance of pokeball colours should not be completely random. If one hasn't appeared for a while, make it appear kind of thing. Otherwise when there gets to be many kinds of pokeball, some colours may not appear for a long time, long enough to lose the game quickly from having been doing very well just because of that one stack of boxes with the colour on top that just won't appear.
It's also hard to tell sometimes how close you are to getting the ball on the intended square. Sometimes when it looks like it hit the box doesn't disappear.