This game is addicting and challenging. I've spent a lot of time playing it over several months, but I'm fed up with the ads. Every time a puzzle is completed/failed you get an ad. You're able to skip it after a few seconds but it's an interruption nonetheless. I really like this game a lot, but I'm giving it 1 star because there is no way (currently) to remove ads. They've become such an annoyance that I've decided to uninstall the game entirely. It's a shame.