Farming and upgrading hero is what I love to play, but so far the interaction with other players still have room to improve, it is more like a single player game for now.I am sure there will have some more features in the future.Also, a fast mode should be add in the game, it is a bit boring especially trying to beat some hard lv campaign which is a waste of time. Of course same thing in the arena. Moreover, I think it is meaningless to have a cool down in challenge mode. To me, I just want to finish it in a minutes and leave it alone rather than re open it again and again every 5 minutes....