This is a pretty satisfying number goes up game. I do wish there was more of a reason to go back and do the lower levels though. Maybe an elusive bug you couldn't get before. Not just rare ones but ones you need higher tier upgrades to get. The rare ones are ok but since they take a while to show up and don't give big money, I am not really incentivized to get them. I am incentivized to get to the last area and just rack big bucks from there though.
Overall great game