Nice job. Perhaps I would move to a color palette that highlights more the enemies and player from the ground, or another option would be to add an outline to them? Now, it gets too much blend with the ground in my opinion.
I think you’re right. The game has a border for stronger enemies (rare/elite) but nothing for common guys.
I’ve been playing around with the sizes of each enemy but I think the colour palette is the way to go and I’ll look to update it in the near future.