2D fixed screens, and an *extremely* minimalist and claustrophic style (few tiles)
Survival metroidvania game with some dystopian and horror elements.
Heavily integrated with its lore, which isn't extensive but just ties in heavily to the overall immersion.
While the terrain is procedurally generated, there are various "regions" in the map that have fixed properties and are eventual locations to access.
Has a skills system for absolutely everything.
The death mechanic is literal quantum immortality -- you keep your skills, village standing and progress, however lose your items and the map totally regenerates. It opens in the same way as the beginning of the game, except the Worm there is just doing the boring part of his job and isn't excited. Your first death will at least get you some different dialogue however, as well as unusual deaths.
"Wormville" is the name given to the town you start out in. The society is divided into two very distinct classes:
Worms -- most of the people are in this category, and tend to have prefixes related to that based on their jobs, like Wakeworms, Lightworms, etc. Though there are exceptions like "Mossers" or "Yakhands".
The Opulent -- the other class. Rarely seen outside of the gleaming gem-based entrance to their space known as "The Opulence". The entrance is guarded by people with gleaming golden swords known as The Gracious. They have metal wings and also various metal things all over their body, making them resemble cyborgs, though they're fully human. They also have fearsome fully-grown and armored 'Yotes known as Cerberi that help stand guard.
Worms exist at the periphery of The Opulent, which has a lot of natural gas veins which are rented out to the Worms. The Worms have to pay a kind of rent on their Gratitude day (which falls at the end of the week), which is one of the few times the Opulent come out. Rent, and currency in general is handled by "Ameths", chunks of amethyst that have been minted by The Opulent.
While there's a kind of local economy, most of the Ameth production comes from various jobs (known as "grinds") run by the Opulent that either add to Wormville society or add something of value that's taken in by the Opulent and never seen again. This work tends to be excruciatingly boring, hard and with long hours. But the rent structure isn't too bad, which allows people to spend Ameths on other things to improve their lifestyle or social standing. Not paying rent for whatever reason breaks Charter and leads to some pretty rough punishments.
Light
People here naturally produce their own light (which is important as the caverns are naturally dark), however the caveat here is they have to eat a lot more in order to sustain that. That isn't particularly difficult, as even sparse areas of the cavern have Quantum Mushrooms or other food sources. In Wormville, Yak Butter provides a lot of the calories of their diet.
Moss
Moss is a plant that grows slowly on its own but grows a lot quicker with light sources. There's a grind known as Lightworms that involves clustering people together near Moss and overfeeding them things such as Ghee Drips so they put out more light. It tends to be pretty unhealthy over the long term but over the short term is a pretty sweet gig that also solves your food problem throughout the day.
Moss is a part of the human diet (though not a strong one), but its main point is in feeding Rockworms (like literal actual worms) and especially Yaks. It's also a strong fibrous material, so it's turned into clothing, sleeping bags, etc by craftworkers known as Mossers. A "Moss Rag" is a very basic cloth garment that's given to Grubs (new people) or Oldgrubs (people that have died and been resurrected at the same stations) and tends to be highly cheap. It's a kind of robe that's tied to the body at various points.
Yaks
Yaks are literal Yaks (to a large extent anyway). They feed on Moss and produce dairy products such as Yak Milk and Yak Butter. Their fur is also a warmer and stronger textile than moss if woven correctly, so a craftworker known as a Clothworm will turn it into a useful textile which is usually bought by The Opulent -- however less precise versions are a good clothing choice for exploring colder areas of the cave system, so they'll also sell Coats and such for those reasons.
Eating Yaks is strictly forbidden by Charter, however if they die naturally, some of their meat will be served up at the next Gratitude, with the rest going to the Opulent. Whatever the butchering process is, it happens inside the confines of that world -- dead Yaks are shipped out there ASAP.
Yaks are bred and their calves can be bought, which allows ordinary people to make their own yak products potentially -- however The Opulent buy a lot of yak calves, possibly for eating them so there tends to be a shortage.
Yakhands tend to specialize in either raising yaks for dairy products or breeding them, with the latter being a lot more profitable but also riskier.
'Yotes
'Yotes are domesticated coyotes. Some breeds can grow to an enormous size, however to do so they have to be fed strict carnivore diets, which is very difficult for a worm since their diets are based around mushrooms and dairy and there's a lot of random meat restrictions in Charter.
'Yotes serve a similar purpose to dogs -- they can help herd Yaks and make particularly good sentries, and also help explorers avoid danger and will fight off things elsewhere in the caverns (or more likely, die trying).
'Yotes are highly intelligent, and this (and sometimes their size) scales according to the amount of meat in their diet. Smart 'Yotes won't pick a fight they can't win, unless it helps their owner escape. They can also sense danger before people can and will alert them.
The game is 2D and top-down but it's *extremely* claustrophobic (there aren't very many tiles per screen) and minimalist (white tiles on black essentially, or light gray on dark gray if that looks better). The point of this is to ramp up the claustrophobic aspects of the game and its eventual horror elements.
As mentioned, it's a Survival game. You start with some amount of hearts (5?) displayed as the literal ascii symbol which turn into the hollow version of them when removed. You also get hungry, though that's relatively easy to sate.
Quantum Mushrooms
A big part of the early game are Quantum Mushrooms -- these will randomly change locations and regenerate in real time if you don't collect them fast enough (though interacting with them will keep them locked in place).
They contain both a cap (edible) and a stalk. The cap is protein-rich while the stalk is vaguely woody and serves as a replacement t for sticks in the game.
Various rocks are lying around and are collectable. Mining bigger rocks can sometimes also make smaller rocks of various types shard out. An important one (relevant here) is Flint.
There are occasional Gas Pockets. These can have Flint thrown down inside of then, which will ignite them into a kind of replacement for campfires.
Lit Gas Pockets can be used to harden mushroom stalks into something fit for making Tool handles.
Pickaxes
Of course, your main Tool of choice in Petraphobia is going to be the Pickaxe whose basic form requires a sharp stone (found or pushed out from larger rocks) and a hardened mushroom stalk. Pickaxes of this kind aren't very durable but they should have some uses albeit slow ones. Using this kind of pickaxe also makes you hungry.
Large rocks will contain metal ore a ways into the rock and metal nuggets more generally from Fracturing, with some rocks being better suited to this. Metal is the next progression step.
Clay and Shovels
Near sources of water, you will find Clay deposits. You can walk on Clay but it slows your movement speed down.
To get Clay you need a Shovel, which can be crafted from a Scoop stone and a hardened stalk. Like the Pickaxe, these have low durability.
Clay can be crafted into Wet Clay Pots, as well as Wet Kilns (which are quite large inventory-wise).
Putting a Wet Kiln on a fire will turn it into a Kiln. Any wet Clay product put into a Kiln will harden into the hard version of it, for example a Wet Clay pot.
Metal Use
With a Clay Pot, you can turn metal Ore and nuggets into metal ingots. This then needs to be poured into dry clay Molds, which have had water placed into them collected via Clay Pots. From there you can make various metal components such as better versions of sticks and rocks -- these tools still break, but their durability and speed is higher.
The game setting has several types of monsters, the latter two of which aren't explicitly named except in rumor and legend. Monsters as a whole are referred to as Elds.
Eldeer -- Generally non-aggressive but sometimes territorial, usually they'll leave you alone if you're not too close and also leave them alone.
Eldrits -- Aggressive variants. Sometimes they'll even seek you out or chase you down. However like Eldeer, they're not super harmful.
Eldritch Colossus -- A massive variant of an eldrit. Quite deadly. They are however quite rare.
Petra Colossus (Petracolo) -- A massive variant that's composed of the rocks in the setting *itself* -- sorta influences the game name here.
