Sgt_Rock put together a "flat look" 2D ground tiles graphics mod. It replaces the 2D tiles for the HPS/JTS Nap series (goes in Map folder).
Instructions:
1. Download the file.
2. Open up the zip file once it is done being downloaded.
3. Open up your HPS or John Tiller Software Nap series title main folder.
4. Find the Map folder. Open it up.
5. Using the Zip file as your guide, find the files in the Map folder that correspond to the ones in the zip file. Make a new folder in the Map folder and call it "Stock Artwork". Put the older files from your Map folder into this new folder.
6. Unzip the files from the zip file to the Map folder. You should not be overwriting any files if you follow these directions correctly.
Here is how the new art pack looks for the Double Contour maps (levels 0-26):