TLDR* at bottom of the page.
I understand the blue in the tether line is supposed to represent oxygen, however ;), what if like the ability to customize the colour of your space suit, allow a player ( once unlocked lets say a ' colouriser' ?) the player can choose the colour of the tether cable or cap ( something to help distinguish it from other tether lines ) this would be extremely useful in cave exploration as a player could mark their path out in lets say Green, a path to a resource deposit ( in a corresponding colour using a preselected/created colour pallet ( of X amount of colours