In this topic (https://www.lemmingsforums.net/index.php?topic=4963.0), an image was posted showing regular lemmings, neutrals and zombies in CPM. It occurs to me: the zombies are hard to distinguish from regular lemmings. I would suggest making them green (dark for without permanent skills, light for with). Green tends to be associated with poison and infection in video games.
There is a further color not shown in that pic for selected lemming. Assuming it doesn't conflict with that (I don't remember off-hand), this could be considered.
Ah, sorry. I didn't realize there was another color for that, so I didn't think to include it.
Green would work if it doesn't conflict. Purple could work, too, for the same reasoning Proxima has stated for green.
Any further input on this? If not, I'll change the non-athlete zombies to some shade of green, and leave all others as-is.
Okay so it's not quite "leave all others" as is (specifically, other zombie variants will have changed - non-zombies of all kinds will still remain as-is), due to the exact way it works. But, implemented in a89a731.