At the outset, the game generates a house along a 2D grid via magicsel, with a couple doors leading out into an area one tile thick stairstepped with developed resources.
The area one tile stairstepped out from that is developable -- once a tile is developed, all full-adjacents will also be developable.
The world is "infinite" but you can't move outside of developable tiles.
The time system is a bit different -- events will advance over days, but there isn't anything that happens within a day, so you can have days that last longer than 24 real world hours or days that are a couple seconds apart.
To advance the day, you sleep in a bed. One is available at the outset and can't be broken down/whatever to prevent softlocking. It can be moved however.
Sleeping takes real time (depending on its ornamentation), and also advances hunger and thirst, which also play out on a day by day basis. Same deal for Freehands.
Hunger and thirst increase the amount of real time it takes to do various time-based stuff. This can get pretty ridiculous, so it's good to get a good supply going early on. Eating/drinking removes all deleterious stat changes here and fills your hunger/thirst bar by some amount, and might grant perks as well.
Tile development turns an undeveloped tile into a developed one, making all inaccessible adjacents undeveloped.
You can develop anything whatsoever on any kind of tile, however each tile has different strengths and weaknesses. This isn't random -- a wilds-style algorithm makes box-like areas where things are better in some capacity. This can then overlap with other boxes so you have to choose.
Tile Development uses the elements system, which has been explored as nauseam elsewhere -- each item has an element associated with it, there's ways of making weaker and stronger forms, and more advanced ways of transmuting one into another.
You can also just expand your House -- this instead costs aether and it has to be orth-adjacent to another section of house. Adding a door to the outside world will cost additional aether, and you don't get this back if you decide to expand in that direction.
You can break down a door or a house segment if there's nothing in it -- this doesn't give you the aether back, but allows you to restructure and use the tile for something else.
Developed tiles offer a limited stock of resources -- there are different mechanics here depending on *what* exactly you're targeting. When the stock runs low the tile becomes "scarce" and is harder to work with, however scarcity might be preferential (this is the point at which caves start producing Gems for example). If a tile runs out entirely it becomes Depleted -- you can't gain anything new, but you do get 1 DP. DP is useful with Libraries.
You can also redevelop a tile at any time -- the cost is the same and it basically resets everything on it. Trees might need to grow again or whatever, but when they're done you have a full stock again. You can't do this with House tiles, which act differently. It will also reset in the exact same procedural way, so if you find some really good POI and memorize where everything is you can farm it effectively.
Plants -- the categories here are all a bit different, but they are easier to harvest with certain tools. These also have to Grow over the span of days before they're usable.
Dirt -- requires a shovel. Gives you things like clay (which require a bucket), insects, sand, loam, and particularly rocks, which are how you form basic tools until you can start digging through caves.
Caves -- require a pickaxe to make progress, but probably also ropes/torches. Bombs can be very effective but can also damage resources (so mapping is a necessity). These give you metals, precious metals, some more obscure liquids, and when depleted, crystals. Interesting mechanics here -- you're excavating the various branches.
Dungeons -- contain enemies, a single artifact, other useful loot, and have doors that have to be unlocked -- you can find some keys in here but will also have to craft your own via that mechanic more than likely (unless you have a good farming setup, or Freehands that do what you want them to do).
Pools -- offer fish and, when they're scarce, Junk. Rarely they'll offer underwater resources like pearls and seaweed -- but you need special equipment for this.
Artifact dungeons -- dungeons that require some specific Artifact and less keys, but are otherwise identical. Also backtrack-intensive puzzles.
Market -- allow you to buy and sell items of a specific type. Markets have a limited amount of gold which depletes selling, and a limited amount of items which depletes buying, however these don't run out concretely or easily, so you don't get DP when they run out and instead just have to redevelop them. There are however bonuses if they're surrounded by other civ tiles, including some kind of restocking.
Inn -- Sell food, drink and fast beds, and also hold a few hireable Freehands. Like everything else, if you redevelop on the same tile you'll get the same exact properties, so it's a good way to farm Freehands.
Luxury shops -- sell things useful for bolstering Freehand stats. The mechanics here are a bit different -- instead of a single tile, it's a whole mini-world that you have to explore to find useful shops. These are also unique in that they have to have civ tiles on all orth adjacents. You can however redevelop a civ tile into a different type if you find a luxury hotspot.
Library -- scanning/blueprint-esque mechanics. These will give you some information outright at 0DP, but they're broken into sections by your DP tier, and everything is paid for via Gold. Counts as a civ tile. These are also how you upgrade your ability to see a tile's potential (the overall amount of properties you can see prior to development).
Fort -- an outpost of enemies. Lots of them. No keys or artifact mechanics but better loot, and rarer types.
Range -- Allows you to hunt animals via the Bow/Arrows/Traps mechanic. Fairly complicated, and functions as a mini-world. Scarcity gives you access to their nests, which have various bits of useful loot, as well as Animal Eggs.
Tile Types for your own use (Base tiles)
House -- expands your house.
Cellar -- requires that there isn't a cellar in orth adjacent, and all four orth tiles are base tiles. Food refinement happens down here, as well as potionmaking/etc.
Hut -- a tile for a freehand to live in. Functions as a mini-world that you expand in whatever way best suits them. It doesn't have to be surrounded by base tiles, and sometimes it's preferable that they *aren't*.
Well -- a source of water. These do deplete, unfortunately, but they'll regenerate and have different "depth" depending on tile properties. Depletion doesn't give you DP.
Farm -- mini-worlds that allow you to grow a specific crop. Useful to expand the amount of resources you can gain easily, or play around with Genetics.
Ranch -- same deal here, but for huntable animals. They eat crops. Plays with Genetics.
Insectarium, Aquarium -- same deal but for insects and fish. Some interesting mechanics here. Plays with Genetics.
Power generation -- there are various tiered fuel production methods that need their own dedicated tile, with the tile in question providing the framework for its properties. Fuel is necessary for various types of advanced crafting, as well as more modern amenities for Freehands (and yourself!). Wiring is definitely a mechanic.
