Really quite poor. Most of the upgrades have a confusing effect. It is not even an idle game. Nothing happens unless the game is open. It is basically impossible to progress without watching ads. I do not mind if a game takes longer if you play for free, but this one was designed to have almost no progress without paying or watching ads for bonuses. Alot of upgrades are unnecessary. You spend alot of time staring at the screen waiting for resources to grow back.