!WARNING! this is going to be a bunch of ideas at once. i prefer to do this over a bunch of ideas and i may end up either making new one later or modify this one. also some ideas are more of add after game is finished that i post just so i dont forget other are thing i feel should be added.
Idea one. Mutations and clothing.
i feel realistically armor and clothing the player crafts will be fitted for and mutations. example i make plate armor but after a adventure somehow i ended up heavily mutated lets go beast for this example. so know my plate armor does not fit. why cant i just smelt it down and reforge armor that fits my size. i mean while this works differently other more rpg game with different races have armor built for that race. so why cant i just modify my existing clothing or rebuild it to match my new form. this also lowers the slime alpha medical and trog mutations of there unfair buff of causing no changes to the body. while its still buff since any clothing fits its not as hard. same with weapons and vehicles they could just be modified for the players form.
Idea 2 More mutations.
some i think a few more mutations would be fun. Snake. like the lizard but more survival focus. weaker melee compared to lizard but can actully dislocate their jaw and eat foes in one like a snake. note don’t do on robots and its not the best early on with zombies. (orginaly i thought don’t do it one them in the first place but i figured it not really worth it with out being able to use it on undead.) Horse a more endurence build huge stamina and being able to have high encumbrance limits. mixed on being able to eat meat since i have heard of horses eating meat at times. more to come.
Idea 2.5 super mutations. and mutation variations
Super Mutations are "alpha"versions of other mutations or new mutations that are to related to other mutations
example Dragon-lizard Naga-snake centare-horse. mutation variations. some mutations are for groups that could be wider like insect. it could be a beetles bees scorpions other insects, slime types from rpg just for fun. spider, black widow trapdoor. you know just added some diffrent versions to some border mutations for a bit more uniqueness.
Idea 3 Blueprints/power armor rig.
side note never actually got power armor so no true idea how they work so take this idea with a grain of salt that i mostly going off how similar it is to fallout 4 power amor. any way i think some powerful item should be able to be crafted but only by blueprints and these are only found in military/lab locations and always behind a locked and guarded vault. and yes power armor blueprints. the power armor rig is a vehicle (and base if bases ever really get finished to allow it) instalment to alow both the crafting and modifying of power armor. it would go in stages for building the frame the exosuit that helps you wear the armor then the armor parts. also this would alow player to mod the armor to fit biology playing a insect mutation with the extra arms? added the frame exosuit and armor for the limbs and then you get a buff for the limbs tho added weight and more resources spent building it all. note this would take at least a week or two to do its not a fast method
Idea 2 v2 mutation changes.
so after some talk it seem people and i say that the mutations should both be more vauge. like canine felin and cattle just become beast but people can pick from diffrent versions of a mutation like why not going both beast-cattle-cow/bull (i did cow/bull since in reality male players would likly become bulls while female would be cows since that just how they are called in gender terms for bovins) or insect-beetle (maybe) type of beetle. or insect-bee/ant/scorpion. lizard-komodo/chamelion/salamander. i would also add more enemy based mutations (yes more mutated npcs either zombie mutants or rabid mutants) what i mean by this is we have a fungus mutation why not something similer to zombie (i call it necromorph and its mostly similar to deadspace necromorphs) and nether based ones like demon/angel (demon would be with the nether angel against)
idea 4 map changes.
thinking that most of the end of the world is more plage based and not tho something like fallout i think some automated systems would still work like this worlds version of apple and amazon that in modern times has robotic run warehouses and shipping depots and amazon air and apple servers. so back to topic with how the world of the game is a fair bit more advancded i would think large companies like those would both exist and have strong buildings that still work in story and thus can be used. servers can be used to well runing things on computers like order things and then get it from a drone (using cash cards to pay added to their high value, or more a reason for their value) and with bases could be used to run more complex systems like large scale ammo or high tech construction like power armor construction/upgrading/modifying.
part2 sewers and subways. i dont like how these are done in game the sewers should fill a good amount of the -1 layer of the world (with the main area being 0) not counting other things in the way and anthill/slime pits. ok so most of the area with towns and citys and connected areas. and they always have to lead to a sewers treatment plant. tho i will add collapsed sewers and subways could exist. same with subways they should connect any large town that has a subway station (with working and collapsed tunnels) and yes i also mean working and rideable trains