I have added a devlog post with some explanation of the upgrades for now, but clearly I need more in game clarity long term.
I see, I thought maybe you came from the tower defense world and were hoping for a more hands on approach. Don't Kill the Messenger is inspired by other idle tower defense games, but that does seem to be an off shoot of the idle game genre as a whole.
As there was not a Idle Tower Defense tag, I tagged with both, Idle and Tower Defense. I could create the Idle Tower Defense tag, but I do worry about getting so niche that no one can find it.
I do appreciate the feed back, thank you for engaging with me.