A fantastic co-operative experience, if you're prepared to commit
The Arkham Horror LCG core box is less of a game and more of a flimsy covering to a deep, deep rabbit hole. At it's best, the game is a co-operative card-based RPG with the players fighting against an array of otherworldy horrors, with strong branching narratives and deep replayability. However, to get there, you may need to look beyond just the base set which is a little bare-bones and punishingly hard as it tries to teach players than the aim is not to win, merely to survive.
As an LCG (Living Card Game) there are several (six at the time of writing, expected to be at least ten before FFG are done) additional story cycles consisting of a deluxe expansion and six mythos packs that provide an eight part campaign and an slew of new player cards to expand your deckbuilding options. It's a big commitment, but it pays it back in spades with a minimum of 16 hours of playtime for a campaign, before you consider a repeated runs with different characters and decisions.
It is a fantastic experience, with very few comparable games out there, but you may have to put in a little effort to see it truly shine.