Looks like there are more files related to the "Road To Death" era
From The Lost Media Wiki
several .ho files in the "levels" folder have files with "zombie" in the name. I have no idea if they correspond to the "Road To Death" era as I have no way of opening the files that are inside those .ho files. In addition, keep in mind that the levels that contain these files are very likely to be used and only those files that I mentioned above must be leftovers from previous versions of these levels.