I wanted it to have sci-fi elements at every level of gameplay (maybe except start from zero).
Mostly light stuff, not big lists of recipes that are hard to maintain.
Some of the ideas to give it a direction:
[ul][li]Craftable laser weapons, to sink electric power into, but not too good[/li]
[li]Exoskeleton that boosts strength (like artifact) when powered, but takes some extra power when turning on (to prevent tedious flipping on/off from being optimal)[/li]
[li]Atomic battery mod as something common rather than endgame thing no one uses. Also minireactors.[/li]
[li]Cloning facility in labs[/li]
[li]Craftable drugs that increase night vision (or at least just pure perception), craftable combat drugs that boost dex+str, but also conflicts between those (could be implemented as mutual resistance making both of them suck if both are active). Long term - think more Witcher elixirs than adrenaline shot.[/li]
[li]Not too many firearms, but perfectly usable pipe guns[/li][/ul]
As for the theme, I imagine it roughly as Fallout meets Stalker: common radiation, mutant animals, drunks with plasma weaponry, a bum in the background warming up next to a trash can filled with green, glowing goo. Light, non-serious, without explicit jokes, a bit morbid.
One thing I’d like to address but I’m not sure how would be addictions: in BN, they’d be a fact of life, not something you avoid completely. The question would be not if you’re addicted, but to what. I’m thinking no growing penalties for severe addictions (just a single level of addiction), easy addiction acquirement but slow removal, and partially overlapping roles so that you want to be addicted to one/two drugs and not 5.
I don’t have a good idea for vehicles (other than more common minireactors). Making fuel rare would hurt gameplay, but I don’t really see gas guzzlers fitting in.