It's fun at first, but you start to realize that random spawns and random merges make most of the units unusable. Units improve through random card spawns, so it quickly becomes a "buy more to win more" game. It doesn't help that they essentially force PVP as the only playmode (if you want to play more then 15min a day), which shows the pay more concept in action and quickly makes even the most skilled plays fail. I'd give it 0 stars due to the time it wasted to figure this out.