Too many ads, just enough content to hook. Its an ad trap, really. The regular levels never get any harder, Im on 85 and I wouldn't be surprised if they werent all unique. The challenge levels seem challenging enough to make them worth working towards to unlock but they're really just a larger version of the same lackluster "puzzle". This game added enough side collections to make you feel good but really they're worthless too. There's an add after every level and not the quick kind either.