A few suggestions

Ok so this is going to be a fairly long post with as much detail as I can bring to it so the ideas are clear.

First off the tech tree:

This needs to just go, in it's current form it doesn't feel right and doesn't seem to fit. If it is going to be used for RPG elements then it needs to be for Player improvement, better endurance(longer lasting stamina) better weapon handling (improved recoil handling, faster reload etc..) Improved mining (improves your mining drill for better ore drop rates)...

A few suggestions