There is a help in the main menu but it's incomplete. I do need to make that a lot better. My vision for the game is to be a lot about exploration this includes finding new items and the little 'game mechanics' that they bring with them. I find that when I play a game (say a strategy game like stellaris) what I enjoy more is discovering the interface and mechanics. Once I know these things I tend to lose interest. So for taxinaut I wouldn't really want to create a codex that talks about all these things. That's why all the items are together in one panel. I want there to be a sense there that there are no rules to what items can do/entail. I agree the galaxy-map and some other core aspects are badly documented. But I don't think that there are really that many of them. The items you can get should be able to explain themselves pretty well through their hover popup.
I will see if I can add sub-titles to the youtube videos, would that help? I'm thinking of making another one in which I explain some aspects a bit better (e.g. galaxy-map and passenger pick-up).
Really enjoying your feedback b.t.w. thank you very much for that!