Currently it’s really hard to know which stations are upgraded and which aren’t, and just as hard to click through each one and know you’ve hit them all. On top of that, I’d say it’s too difficult for a layman to remember which research upgrades apply to each station. My suggestion is to:
- Add a way to cycle quickly between all stations (brackets, carrots or some other binary keybinding)
- Add UI after each research category is completed that points out which production station it applies to, and
- After a research category is upgraded, add a button to upgrade all applicable stations
Long-term it might be worth looking into a way to easily view which stations are fully upgraded, though that seems like a pretty hard UI challenge. Maybe some kind of station “rating” when you’re at max zoom. (i.e. the way that Cities Skylines has a visual “bar” rating to show how upgraded a building is, like 2/5 bars.) Seems like that would be fairly cluttered though.