How do I make it fit the entire screen? Changing the resolution doesn't seem to do anything. :(

I love this game. I wish I could play it on the entire screen in all of its glory. I'm not very computer savvy though.

IIRC, there are only three resolutions to choose from.
Maybe your monitor has got setings that will zoom in, i.e. display them on he whole screen .

You need to set the scaling options on your graphics card to full screen as it sound like it's turned off.

Can't help you with amd graphics cards as i've never owned one. I think they have a shortcut in the bottom right of the toolbar where you can change your settings.

If you are using an Nvidia graphics card you can right click on your desktop and there should be nvidia control panel about half way down. Left click that and it will open up the panel window, On the left click display and it will open up some more options. Then click adjust desktop size and position. Then on the main page select full screen from the 3 options and make sure you click apply before closing. Now all games will be set to fill the screen.

Yes, as thornton said, you have to change the scaling option of you video card. It worked for me when I choose the GPU to do the scaling (geForce 660 + Windows 8.1). Actually I had the opposite problem: I wanted to make the game to run in the original aspect ration, because it was too squashed in widescreen.