I got the core game and it is easy enough to learn to play, I think the hardest learning curve is possibly deck building. Like if you mix and match different factions you have to decide if you're going to play with hero or villains. Other than that it's fairly easy to learn.
I have a question concerning expansions. If I wanted to buy expansions, since the game has been out for a bit is there any particular expansions veteran players would suggest over others to start buying?