King Under The Mountain's gameplay is inspired by Dwarf Fortress, The Settlers and Dungeon Keeper, and it has an art style inspired by Prison Architect and Rimworld.

The game world is built on a series of interlocking systems which combine together to simulate a living, breathing world. As night changes to day, trees and plants will grow (or not) based on sunlight and rainfall. The local environment and changing seasons have effects on the native flora and fauna. Your settlers and other characters have their own personal social and physical needs that you’ll have to fulfil to keep them happy (or at least stop them from breaking and going insane!)

Every map is randomly generated from an initial seed (a large number) so that no two maps will ever be the same – unless you choose to use the same seed! The art assets for the game have been created in such a way that they can be drawn by the game engine for near limitless variation in colour – so every tree, plant and character will have their own unique combination of colours and appearance.

It’s an important design goal that it’s possible to play the entire game without getting into armed conflict with other factions (if you choose to). Although weapons and combat can be significant parts of gameplay, we wanted to make sure you can peacefully build up a fully-functioning town to have the satisfaction of sitting back and watching your settlers go about their business in an “art farm” style of play.

King Under The Mountain will be available through Steam Early Access on November 24, 2021 at $24.99/£19.99/€20.99 though there's a 10% launch discount for a week.

“It's worth pointing out that this feature roadmap can and probably will change over the course of development, but here's the current set of features that are planned to be added over the Early Access period:

• Historical records and engravings: Relive and refer to historic events in your settlement's past as your stone masons carve out grand tapestries in stone!
• Jobs: Runecrafting: One of the more "end-game" gameplay features is the ability of dwarven runesmiths to imbue weapons and equipment with magical abilities via the mystical art of runecrafting. Training a runecrafter is a very slow and intensive process, but attracting them as an immigrant requires your settlement to have a lot of prestige, which is a game mechanic to give an actual use for:
• Nobles and their demands: As your settlement increases in prestige, you'll start to attract the attention of members of the (initially dwarven) nobility. These dwarves don't work and make sometimes unreasonable demands of the rest of your population, but have the bonus of increasing your prestige by inhabiting your settlement.
• Traps and advanced mechanisms: Building on the basics of mechanisms, more advanced traps and mechanical features.
• Other races and civilisations: The world of King under the Mountain is home to a lot more than just dwarves, orcs, elves and humans. This update will look to flesh out the other inhabitants of the world and their impact on your society.
• Hostile invasions: Up to now the worst you've had to deal with is aggressive creatures and monsters. The increasing wealth of your settlement will start to attract small bands of bandits and marauders, right up to whole armies from other civilisations attempting to take over your turf! Balance it out a bit by being able to build fortifications and defenses.
• Capturing prisoners: Whether for ransom or otherwise, coming under attack means you'll have the means and opportunity to take prisoners of war. Do with them what you will, but be aware of the consequences!
• Law and justice: Not every settler is happy to contribute to the community fairly. Your military also doubles as a police force for the occasional law-breaker, who have their own methods of dealing out justice.
• Food spoilage: No longer will your harvested crops last forever, you'll have to plan more for the seasons, particularly the winter frost. Salting or smoking meat is an alternative! This will also include harvested crops rotting faster if they're left unpackaged, compared to keeping them in a crate or sack which will have to be produced separately.
• Raising cattle: Rather than always hunting for meat, you can raise farm animals too, though they'll need to be supplied with their own food and water.
• UI Redesign: When the basic necessities are in place, the very placeholder programmer UI will be replaced with something a bit nicer.
• Other biomes: New and interesting locations to found your settlement rather than faux-European woodland.
• Play as orcs: Differing wildly from a dwarven settlement, players can take control of an orcish tribe which has its own mechanics and gameplay concepts. Orcs are always on the lookout for a good fight, and if they haven't attacked anything for a while, are liable to turn on each other! This can be mitigated by building combat arenas to pit combatants against each other which orcs love to watch and cheer on. Even better if it involves some captured prisoners!
• Play as humans: Whereas in most fantasy settings humans are the default or "average" race, in King under the Mountain they are ruthlessly capitalist narcissists, who will only work on a job if they're being paid to do it. Unlike the comparatively socialist dwarven communities, managing a human settlement involves actually paying for jobs and time, in a manner a little like the Majesty series of games.
• Endgame progression: While this isn't well defined at this point, we definitely want to add a bunch of gameplay features and "soft goals" for players to aim towards without compromising the sandbox style experience of the game.
• Noble progression: As your settlement amasses greater and greater prestige, you'll attract increasingly powerful nobles, from counts and dukes all the way up to the king of your civilisation, truly letting you become "King under the Mountain".
• Bards and musicians: Sometimes a travelling minstrel may stop at your settlement and play some songs for their keep, or perhaps one of your residents will take up an instrument (possibly a noble) and play to entertain your other settlers. All in all, it's a glimmer of rest and relaxation in a world of work and danger, boosting the morale and happiness of your population.
• Kickstarter animal choice fulfilment: One of the backer rewards from the Kickstarter campaign allows backers to pick a real-world animal which will be implemented into the game, and by this stage we want to get them all in-game!
• Nemesis System: Inspired by Shadow of Mordor, your settlement may be terrorised by a recurring villain character who will be a constant thorn in your side until you deal with them permanently, which may be trickier than it sounds.
• Family, friends and rivalries: The basis for relationships between settlers and the impact that may have on their thoughts and behaviour.
• Speech and thought bubbles: Help bring your settlers more to life by visualising their thoughts and conversations.
• Clans and politics: Greatly fleshing out the relationships between characters in a settlement, your population will belong to one of several clans which may have their own goals and desires differing from each other. Poor management could live to a civil war!
• Hidden cults: Along the same lines, your settlers may be subverted to a secret cult which needs to be rooted out and exposed before it endangers the whole population. Might end up also including religion as a wider feature.
• Diseases and contagions: It's all fun and games until someone loses an eye (to a horrible wasting disease)
  Alchemy and potions: While dwarves tend not to dabble in alchemy, humans and some orcs have been known to brew potions with varying results.
• Magic system: Also where dwarves don't use magic, humans and orcs both do, and having a magic user in your settlement can bring both powerful benefits and dangerous risks. You can read about the in-world design of the magic system here.
• Demonic invasion: The biggest risk of magic is that continued use attracts demons who can invade reality from their own plane of existence. As some of the most dangerous creatures in the world this risk is not to be underestimated!
• Legendary weapons and items: Also covering some part of Kickstarter backer fulfilment, sometimes crafters will be inspired to create a legendary item of immense worth which may have its own special abilities and/or backstory.
• Books and knowledge: Finally a use for nobles - authoring books and recording knowledge. Of particular importance to wizards and other magic users who can greatly increase their power by learning from the experiments of a more experienced caster.
• Spellcrafting: Following on from amassing magical knowledge, actually building that knowledge comes through spellcrafting - experimenting and trying out new spells to see what works and what doesn't, possibly with comical unintended effects.
• Mythical beasts: In the forgotten corners of the world there are still mythical beasts and monsters, ready to be discovered by an unsuspecting miner, or for them to come across the settlement by themselves!
• Guild masters and detailed job assignment: Rather than your settlers being able to figure out what jobs need doing by magic telepathy, they'll have to report to a guild master for their specific profession (in a larger settlement) who will be keeping the records of which jobs need doing where.
• Bear and horse cavalry: While humans may ride horses into battle, dwarves and orcs prefer specially-bred bear cavalry.
• Kickstarter design a race backer fulfilment: One of the highest tiers of the Kickstarter campaign allows backers to design a non-playable race to inhabit the world of King under the Mountain, and by this point in time we should have them all in-game.
• Asynchronous multiplayer adventures: The flagship feature that we're building towards is not just being limited to your own settlement, but potentially all those of other players too! In gameplay terms, this will mean putting together a small team of adventurers, usually the best and most distinguished of your military, to be sent off on an "adventure" to another location. What we're working towards is that these other locations will be a copy of another player's settlement, probably belonging to a different race (e.g. sending a band of orcs to raid a dwarven fortress), with the goal of taking loot and resources from the enemy settlement. The player of that settlement won't actually lose anything - this is just a copy stored on a central server to act as a piece of player-driven content to provide much more varied and interesting locations than could be created through procedural generation techniques. It's best described as something like a dungeon crawl with a party of heroes from an RPG, but with the characters that you've built and nurtured from your own settlement.
• Turn-based combat system: While simple exploration of other player's creations is all well and good, to really bring things to life most adventures will involve combat with the defending guards and other characters, playing out in a turn-based tactical battle inspired by XCOM, Fire Emblem and even Blood Bowl. The size and shape of rooms and corridors will have different tactical considerations - a narrow corridor may only allow for one or two characters to progress at a time, while a large, open hall will mean relative positioning in a battle becomes a focus. The hope is that these considerations will make designing and building your own settlement even more interesting as you plan for how it might best be defended from other players.
• Reclaim a settlement: Lost a settlement to invasion (demonic or otherwise)? Itching for another chance at the same map, if only you'd done things just a little differently? With this feature, you can reclaim a settlement you've lost by sending a hardy band of adventurers to clear out the hostile invaders and bring it back under your control (going from a turn-based combat adventure back into normal play).
• New game plus: Accomplished everything you set out to do with your current settlement and looking for a new challenge? Rather than starting again fresh with the normal starting set of characters and resources, send a section of your current population along with caravans loaded with goods and supplies to found a new city in style. There's a whole world out there to explore!
• Conquer your enemies: Not content with starting a new settlement from scratch again? Put together the largest, meanest military you can and take over that enemy settlement that's been attacking you. Then, have the option of switching to your new location permanently with a group of optimistic emigrants.

A detailed roadmap is available here.

As well as different ways to build and grow your settlement (do you focus on mining? farming? crafting? buying and selling goods?), in King under the Mountain you can play as several different races and factions each with their own unique gameplay elements. You could build a dwarven fortress dug deep into the side of a mountain, a town of humans at an important river crossing, or a tribe of orcs hunting and raiding others. More than just different races to play as, we want to introduce completely new play styles as unusual factions – perhaps a lone wizard building their secret lair with golems they have constructed, an evil necromancer raising an army of the dead, a dragon amassing a hoard of gold in a giant cave system, or even an invasion of demons attacking the material world.

Have you ever spent hours in a creative game building something, only for it to sit hidden away on your computer? In King under the Mountain, players can opt-in to automatically upload their settlements for other players to visit. This drives the basis of the adventure mode – you put together a party of champions from your settlement’s population, and go off on an adventure to explore another player’s creation. This mode will involve turn-based tactical combat as you explore and battle through another player’s fortress, claiming rare resources that may be difficult or impossible to acquire otherwise. It’s important to note that nothing will be lost by either player in this encounter – you don’t actually “attack” the other player, only a copy of their settlement, and there are benefits to be gained by both parties.

Another big design goal is that everything you see or read in the game (and the variables behind them) are fully open to modification. In fact, the base game is built as an engine with one base mod applied to it (which modders can look at to see how things work).

King Under The Mountain is in development for PC (Steam).