a strange world where whatever collides

this has been worldbuilding in my head for a while now and i wanted to put it into words :D

inspiration from Monoki's webseries and things, veeery loose inspirstion from Ratchet & Clank, Chibi Robo, and Vocaloid/UTAU.

characters

there's a fair few characters but only some i've settled on a bit.
in the not-so-distant future (like around ~2028-2035) there came bio-engineered beings, in which were made by multi-billionaires for... less than ethical and moral reasons. these were to test things (often dangerous) things that humans wouldn't dare do.

however, these billionnaires quickly forgot about them since the "great economic crash of 2029" where the Earth had hit its first climate tipping point, there was large-scale unrest and bigotry, and it was honestly a nightmare to live in.
these beings all came from various different nations, all of which were dabbling in high-tech things and bio-engineering. so not all beings will speak perfect English but most do.

let's start with some characters.

Fukai

age: basically 17
pronouns: she/it/they (from most to least preferred)
species: kemonomimi (mild hybridisation of other animals with humans) - catgirl (based on me the creator who's also a neko :P)
role: not particularly amazing at one thing but often goes to different things per her interests/hyperfixations. but her role in the crew is her ability to record events, archive data/software, and some mild help around the place.
favourite colour: yellow
style: feminine

Boboki

age: basically 29
pronouns: she/her preferred but okay with any
species: anthro (rabbit)
role: engineer, 3D-printing various materials and parts for structures, helping with work with her mecha
favourite colour: violet
style: feminine

Ace

age: basically 24
pronouns: he/him
species: human (one of the few true humans)
role: leader in charge of most things, but often a little laid back
favourite colour: spicy red
style: androgynous

the world(s) themselves

all the initial ~120 characters each formed various sized groups in different locations on Earth before teaming up to form a massive group, to colonise Mars.

Earth

the Earth is done for, only months after the large team settled onto Mars, the Earth became inhospitible for human/humanoid life, humans went virtually extinct and the team could do nothing but spectate through some observatories on Mars.

i said it was one supercontinent before, but i've changed my mind. it's based on the real-world Earth in its entirety.

Mars

colonised, but not terraformed at least yet.

of all places, the large group built underground cities, with the parts peeking above the surface usually containing observatories, satellite dishes of sorts, etc.

initially, some built some above-surface metal boxes as shelters (kinda inspired by the way some research stations in super cold climates on Earth can look like) but these ended up being too dangerous even inside.
however there was also some structures being built underground, which ended up forming the city Rokudai (nicknamed "the city" sometimes) with a total population (after around ~17 months since they settled) being around ~1,010 with most people being civillians, some are crew members to help keep the colony up and working.

the city is underground yes, but there's plants being grown underground. there's LEDs all the time for lighting (typically similar to an Earth city at night since there's no "sun" down there) and it can look weirdly cyberpunk, but it's nowhere like that in terms of the society itself.

minor things

the most commonly-spoken language is English, but it's common for people to be bilingual or at least can understand a language without necessarily being able to speak it.

English is around 43% of the total population's first, native language, while it's around 79% of the total population's second, third, etc language and can at least speak it, with around 94% of the total population being able to at the very least read it.

Japanese and Korean are also commonly-spoken languages, with about 49% of the total population being able to at least speak Japanese and around 34% of the total population being able to at least speak Korean.
Chinese (mainly Mandarin), French, German, among various others do exist as well, but are minority languages.

most signs are bilingual/multilingual, and schools teach various languages in which you may pick whichever one for your main language.

the most commonly grown plants are ones that grow quickly, are hardy, can last without much water/sunlight, or are virtually necessary to survive.

bamboo is grown a lot while the first few trees have been planted -- bamboo since it grows quickly, is a good substitute for cotton, wood, paper among other things - all of which the colony doesn't have massive crop farms for.
lots of microgreens and even mushrooms are grown (mushrooms especially thrive and in some places they grow where people don't want them to) but this has all been carefully planned out to avoid an ecological disaster.

fun fact it's kinda humid as well. people haven't correctly predicted how the humidity would go but initially it was planned to be around 45% humidity, but it's on average 70% humidity all the time. while the average temperature was initially expected to be lower (about 15-20 degrees celsius) but it's actually 28-31 degrees celsius on average in places with more plants and life,

every single material (that can be recycled) is recycled. they don't have forests or quarries like on Earth, and the old rusting settlements (made in the beginning, above the surface, sorta inspired by cold-climate research stations on Earth) since they were left to rust and erode, they were simply too dangerous to live in.
so all the materials from that were recycled.

also most of the structural building components are 3D-printed.
structures are more easier to make, instead of the way they're usually built on Earth - usually these are built with a ready-made frame, the 3D-printed plating (for the walls) goes in, the floor slots in, then from there it's a matter of insulation and checking if the structure is hospitable enough to live comfortably in. (god the regulations are kinda strict but i don't wanna go into that in detail okay lmao)

there's ready-made walls with both the plates and insulation - there's walls that go against the martian earth (which are less pretty, thicker, and has better insulation and usually where cords, pipes, etc go) while where it faces the city they're usually more like white thinner plates.