There is an ad after everything you do. Don't want to upgrade? Watch an ad anyway. Just clicked off an ad but it lagged? Watch another ad. Literally the most annoying ads, too. Not interactive, and switches between like 3 different ads that you'll have memorized after playing this for like 5 minutes. I don't care about the OTHER games on this site, I wanted to play this one. But I can tell you more about the ad games than this one - given this one is just "add bigger number to current number."