This is almost an ok game. The upgrades cost too much. The only way to upgrade is to watch ads. I considered paying for the no ad version, but I guessed that would only eliminate the banner across the bottom of the screen. I read some reviews, and it sounds like I was right. I don't think the developer cares. As long as we keep hitting the ad button. I like the game. I am up to level 185, but it just isn't worth the ads every level.