As mentioned before, I'm adding an option to have a smaller graphical user interface (GUI). This is especially useful for lower resolutions where widgets become really big and are overlapping.
I'm designing the GUI elements in my own 2D graphics tool Plasma (screenshots 4-6). It is based on a self-made 2D engine for displaying scalable graphics (similar to vector graphics). Plasma Engine supports Direct3D and OpenGL an can be used for things like GUIs in games. It also features edge-based antialiasing and animations. I'm developing it alongside Cube World and I'm planning to release it when it's more developed.