All parts of the interface (bar on bottom, minimap, text boxes) scale with different resolutions - i.e., they shrink as your resolution increases. This means at higher resolutions, everything is too small. Personally, I think this is the wrong way to do it. It should instead be like Warcraft III, where the interface is a fixed size regardless of the resolution. Or, at least, the size of Demigod's interface needs to be significantly increased at higher resolutions (like 2560x1600).
Example of the problem:
Demigod at 1680x1050 (reasonable sized interface)
Demigod at 2560x1600 (teeny-tiny-isty-bitsy sized interface with text boxes that give you migraines to read)