Blood doesn't have the map mode from Doom that show you were the enemies are. You could load the map up in mapedit and look where they are all placed when the map starts... but if you don't know mapEdit, it's probably just easier to run around the map again. I'd check the water areas as critters can be difficult to pin down when they are swimming.

As far as what is considered an enemy, mimes do not count, I don't recall specifically if bats and rats count. I don't think bats count, but I'm almost certain rats do. I know that spiders count, and if you run into a mother spider, she will belch out spiders indefinitely. This can allow you to have a excess number of kills ie. "Enemies Killed: 123 of 28"

I have tried to go around and got into all the water I could find, plus checked some videos on the tube, and nothing. Oh well, it seems there is no real point in doing so, anyway.

Can infighting be a reason not to get 100 percent ? Do enemies killed by other enemies count for or against your final score? I don't remember.