Brief. In advanced graphics settings, change the setting Texture Quality to "Balanced" or "Quality". Setting this to "Performance" can result in extremely blurry textures.

Generic instructions. The Texture Quality setting is likely in your 3D settings for your graphics card. Typically you can get there by right-clicking the desktop, choosing Resolution, and clicking the Advanced button. This usually opens a tabbed panel, with a tab named after your graphics card. On that tab will be various settings; typically they are categorized (e.g. 3D Settings).

Hope this helps.

Thanks for the info, I immediately had this issue and was totally put off!! You rescued the game for me :)