So the first release of compound production has resulted in some very cool gameplay responses from our community. It is apparent that the atmosphere can result in some outright impossible or unrealistic environmental conditions, such as these two 100% oxygen-concentration environments on the community forums:
Which would result in what is essentially a fireball Earth in real life. There have also been instances of certain important compounds being completely absent in patches, such as 0% carbon dioxide, making photosynthesis impossible. We can get away with some intense ecosystems since a lot of the Microbe Stage takes place on a planet with incomplete biogeochemical processes, but all-in-all, we should introduce some control on compound frequency - for both balancing and realism purposes.
An idea GameDungeon brought up was having certain compounds have a constant amount added each generation - for example, +2% carbon dioxide every turn - to represent geological processes and other important systems occurring in the background. I think that sounds like a good way of adding some balancing, enforcing a soft “minimum” amount of carbon dioxide. I can also see these features being pretty easily interloped with planet customization, where having a more geologically active planet means a higher amount of carbon dioxide being added each generation.
Along those same lines, might it be useful to have compounds be subtracted against once compounds reach a certain threshold, to represent geological recycling and chemical processes that naturally balance out excesses? For example, if we decide that, say, 30% oxygen is too high for a patch, 1% of additional oxygen will get removed automatically each generation alongside any biological activity for as long as the oxygen amount is higher than 30%. This will allow us to enforce soft caps as well. This can also tie into planet customization as well, and if we wish, can tie into a bit more advanced of a compound simulation - if iron is higher than 5%, then the “cap” for oxygen is lower, and the automatic reduction happens much earlier (that could be complicated to track if we make iron get eaten up by oxygen as well).
I think approaching “mins” and ‘maxes” with compounds in this manner would be a nice way to create balance while not outright enforcing strict conformity. If the player inhabits a patch where biological activity forces carbon dioxide down even with a soft minimum, then we can accept that ecosystem as an immensely unique patch. We just don’t want to make such conditions overrepresented in frequency.