I seem to be getting some weird graphical glitch where random parts of the terrain flicker between 2 different tiles really fast. This happens every time I load up a level and it's really harming my experience with the game because it hurts my eyes x.x

You can sort of see what the flickering is like with these 2 badly cropped screenshots:
http://i.imgur.com/Z0l7w.jpg
http://i.imgur.com/z1JrV.jpg

I've tried disabling my second monitor, running the game in fullscreen and several windowed resolutions, not really sure what else to try. Anyone got any ideas?

Edit: Just realized disabling Ground Deco in the options menu stops the flickering. Will be fine as just a temporary fix, the game looks very plain this way.

Have you tried setting it to a fixed quality? The flickering sounds like it could be caused by the "auto" feature which tries to dynamically set the right quality setting.