It was challenging enough to keep me interested, and it was easy enough to make progress without spending real money. Sadly, I had to uninstall the game for the third, and I think last time. It's too disheartening to have great progress completely disappear from one day to the next. I would return to the game to discover treasure chests and rewards I opened last time I played were back like I hadn't opened them, and always gave me worse rewards than the first time. Sucks. Wish it was better.