While there wasn't that much going on, I still liked this. I am really getting used to hearing that music. I think the best part about it is how it was so simple. I wasn't even quite sure what I was supposed to do at first, but it was pretty easy to figure out. There isn't much else to say about this because it's so simple. Of course, it works fine that way.
I guess it didn't really get harder. It seemed like the same number of green balls showed up as the other ones. I could tell the red ones were bad. I now realize it's modeled after the stop sign colors. Not the most creative, but still nice.