Ads ads ads. There's a 5 second ad after every 5-10 second level and a ~30 second ad after every 5th or so level. You're spending the same amount of time watching those horribly boring ads as you're spending actually playing. Their reasoning is that all free games have ads, but they're nowere as malicious and time wasting as this, they also offer ad free plans for "dear" customers. Basically creating a problem and selling the solution. Disgusting.