Thank you so much for the kind words! The yellow things are cells that can be used to reproduce the bacteria/viruses, there is a create cap of 40, after that they will no longer consume the resources of the cell (a cell only disappears if its resources are 0), a better sign for being on max is definitely something that could have been added. The sound options is a direct exposure of the engine's mixer values, which are in the decibel format, with some extra time we could have properly mapped them visually to a 0-1 range which would have made made more sense, but hey, time constraints :). 0 is actually the recommended value since it is the original mix, lower is obviously more silent and above 0 is more of a boos, like you said one might need a new pair of headphones after that haha.
Thank you for your feedback it is definitely noted.