Nothing I have ever experience
The only downside is that there's a small player base as it was poorly advertised and not a lot of maps although the upgrades for cards will make you play them as many time you want but it tends to be repetitive.New players will aslo finds a hard time to understand the game and may envy the cards other players without realizing they already have great cards for PvE and need to work hard for them.
To summarize:If it was advertised properly and they have more maps,it will be a greater game.Rocky start for new players,a breeze for experienced players.
7.5/10 for this