Arkham Horror is set in the Cthulhu Mythos of H.P. Lovecraft. Set in the 20s players are tasked with investigate strange happening in Arkham.
The gameplay consists of using the attributes of their investigator as well as item cards that represent spells, items or other helpful tools. By utilizing these things the player can progress to open gates to other worlds. these gate contain monsters that will then roam around the board. the player avoids these monsters in order to try and go through the gate, once they return they can close the gate. It is through one of these gates that an end game monster will finally appear, it is up to the players to defeat that monster to win.
Pro Each game is unique
The game starts by choosing a random boss and/or heroes. Each turn begins with the myth phase, whose effects apply from a random card in the deck. These effects include monster movement, game-wide buffs and de-buffs, quests, monster gate breaches, etc. You will never know if you will be able to win the game.
Items and skills are usually taken randomly too.
Pro Highly cooperative
Though the rules do highlight "best players of the game" via basic calculations, the game itself is aimed towards collaboration. To win, everyone must commit to the victory, and you often forget about the existence of a "best player".
The game allows players to exchange items or help other players via skills, special abilities and magic. In practice, players often compete their tasks in pairs and more, e.g. they close gates in pairs, where one has to clean the entrance from monsters, and the other seals the gates.
You either choose by yourself or get a random hero, and play with them the whole party (if you were not killed, of course). You and your hero have skills, items, unique qualities and effects, and their story.
The game itself encourages role-playing elements to dive into the Lovecraftian environment.
Pro Lots of choices
Each location offers you different opportunities to trade for and to explore. The imaginary hero class (like tank, mage, support, stealth) is up to you and usually not well-tied to hero abilities.
Even when apocalypse comes, you still (might) have a chance to defeat the planetary evil.