Essentially a streamlined version of its sister game Arkham Horror, many of Arkham's more cumbersome elements have been stripped down in order to facilitate a more fluid gameplay. Eldritch Horror also differs in that rather than being set in a single town like Arkham, the gameplay covers the entire globe, although in practical terms this is little more than a change of skin for the board.
Players select an Investigator character from a range of pre-made options, each of which comes with different attributes and equipment which will affect the way the player acts in the game; for example, whilst some are more geared towards combat, others may excel in the field of investigation or spellcasting. The goal of the game is to prevent the awakening of an malign entity known as an Ancient One which can be done by closing interdimensional portals within a certain time limit. All the while, the players must fight or evade monsters and search for clues which will help them to close the portals.
Since it’s first issue, several expansions to the base game have been released, each bringing some new twist to the gameplay of the core set, along with additional cards to enhance the base decks. These expansions are divided into small-box and big-box versions.