Thanks a lot for your feedback!
- There is definitely something to add to the identification of resources, color is not enough (and not colorblind friendly...). I was thinking about adding a symbol because it's prettier than letter, but letter is easier to communicate.
- Progression based on days was to simulate resource discovery over time and so different eras (like stone Age, Iron Age, ...). There is no logic to discover new resources when the population grows. But as you say this is a problem for initial stages and the course of the game. So we have to add some behaviors to make it more interesting, I think of different possibilities:
- demand (needed quantity) for existing resources changes depending on population
- invest in exploration to find new resources faster
- other kinds of advances based on population (new market upgrade, exploitation upgrade, traders upgrade, means of transport)
Back to work now but i think you have to wait until the beginning of the next year :)