The game presents one of several dynamic story-driven scenarios. Your crew of investigators have been given a tip-off of some dark occurrences at a remote estate (or town, or museum, or...). Arriving on scene, you will poke around looking for evidence, either to bring back to the proper authorities or tell you what can be done immediately to stop the evil plot. Of course, an unknown house full of horrors and secrets stands in your way, and even if you manage to find what you need or stop the dark forces, they certainly won't let you escape intact...
Published by Fantasy Flight Games in 2011, Mansions of Madness received a couple Expansion Packs and several add-on scenarios. A second edition was released in 2016, with the biggest change replacing the role of keeper player with a required companion app. This would make the game fully cooperative or playable solo, and allowed for some replayability with the app able to add random changes to the scenario or the map. A conversion kit was included for owners of the first edition to make use of the figures and map segments in the previous box. The second edition now has four full expansion packs, a number of downloadable scenario additions, and a thriving homebrew community that has released many custom scenarios through their own app.
The game contains examples of following tropes:
- Competitive Balance: Each investigator has different stats; one can be a bruiser to fight monsters, another with high intellect to find clues and evidence, or someone with willpower and sanity to spare to handle the occult spells.
- Coop Multiplayer: In 2nd edition, all players are cooperating to beat the scenario and escape with their lives... but if someone goes insane, that may or may not still be true.
- Demonic Possession: Thralls, introduced in Beyond the Threshold, used to be people. Now, they've had some eldritch mind possess them so completely that they're half-mutated into bestial things.
- Dungeon Crawling: The actual goal depends on the scenario, most of your actions are spent looking for clues and evidence that will explain what you need to do, and you may be in a run-down mansion or a maze of alleys in a seedy town. Still, random ghouls are guaranteed and exploring is key to finding anything, so the basics feel the same. The game owes a fair bit to FFG's earlier title Descent.
- Everyone Has a Special Move: Every investigator gets a small bonus for a particular action, like gaining a clue whenever they defeat a creature, helping to specialize their role beyond their stat makeup.
- Expansion Pack: Plenty of them, in varying sizes, contributing new investigators, map tiles, monsters, and cards, as well as the all-important new story scenarios.
- Beyond the Threshold (2017) focuses on the creepy mansion action with a shifting map and a whodunnit dinner party.
- Streets of Arkham (2017) is a larger pack adding new locations and scenarios from around the titular town.
- Sanctum of Twilight (2018) puts its sights on the rich and powerful members of the Order of the Silver Twilight.
- Horrific Journeys (2018), again a larger pack, adds scenarios aboard a train, a ship, and an airborne blimp.
- The companion app also offers some DLC scenarios for purchase, and two figure and tile collections (Suppressed Memories and Recurring Nightmares) also collect all the First Edition material that was offered and imported to the Second Edition of the game.
- Hit Points: Every hit on an investigator earns a wound card, and every nasty shock earns a horror card. Once you have more wounds than stamina or more horror than sanity... you take a permanent injury or insanity that limits you and makes taking damage even more likely. Earn all the cards one more time, you're a goner.
- Luck Manipulation Mechanic: You can spend clues to turn failed rolls into successful ones... but you have to have been lucky enough to find a clue first, and you can only do this for the dice that have rolled a clue symbol.
- Noob Cave: The suggested starter scenario, Cycle of Eternity, has you investigating an "astrological society" on the Vanderbilt estate. It's a small and mostly straightforward introduction to the game, although it's not afraid to pull the gloves off at the climax.
- Old Save Bonus: Of a sort. If you own the First Edition of the game and/or any of its expansions, the Second Edition box comes with a "Conversion Kit" including all of the player cards and some of the tokens from the First Edition, allowing you to use the tiles and figurines from the First Edition in the Second, playing the old scenarios or using them in new ones. FFG is also selling those figurines and tiles outright as the Suppressed Memories and Recurring Nightmares sets for anyone who may have missed out on the First Edition.
- Random Event: The Mythos phase, as with most other Arkham titles, will toss out unsettling horrors (the lights going out, creepy visions, piercing noises) as well as wandering monsters.
- Town with a Dark Secret: Innsmouth returns for the Escape from Innsmouth scenario. On investigating a local family's connections to Deep Ones, every method of leaving town mysteriously fails and you are forced to spend the night. Naturally, most of the town are hybrids, a rabid mob is formed to hunt you down, and you're forced to gather evidence on the run while hunting for any way out.
- Variable Player Goals: Played with.
- An Insanity card is a hidden condition that changes how you play. Maybe it limits your actions in some way, maybe it changes your victory conditions, maybe you switch sides entirely... or maybe you're just twitchy and jumpy, who wouldn't be. You're not allowed to tell your teammates what it is though. Let the paranoia begin.
- The Hidden Depths scenario from Horrific Journeys introduces Agenda cards, hidden roles tapping some players as humans trying to resolve and escape as normal, and others as Deep One hybrids secretly trying to make sure no humans reach shore. No one is sure who is who, either.