Before this recoil discussion progresses any further, I'm reminded of another suggestion that I would actually appreciate much more than the above two:
There is FAR too much red in this game, or, to be more exact, there's too many things which have the same shade of dark-red. I don't know about everyone else, but my eyesight isn't the best, and this leads me to regularly overlook really obvious dark-red colored things.
What I'm talking about:
Barons of Hell
Former Captains
Large Medkits
lava
All these things will VERY OFTEN be overlooked as part of the scenery, since a great deal of walls are red, as are bloodied floors. With so much red in the environment, I have to really strain my eyes to glean what is and isn't a monster or item or pool of lava. I can't tell you how many times I've been hurt by a Baron that just conveniently blended into the background, because my mind doesn't pick up on it right off the bat, and I often find myself having to get a really close look at the screen in order to make sure what's lava or a bloodstain.
If there's already an option to alter the coloring scheme of monsters, then I wouldn't mind being steered in it's direction, but if there isn't, then I'd like some more variety in the colors of some of the monsters, large medkits, and lava.