The first splicers creeped me out, but eventually they became commonplace, which is a problem. They were no longer nightmarish objects of horror but people with skin problems that seemed to enjoy charging at someone carrying a boatload of weaponry. Not very creepy anymore. Most of my favorite moments were scripted moments rather than random battles. Fighting splicers became a chore rather than a challenge.
Ok, maybe I'm harping on this too much, I'm just really disappointed. I guess its too much to ask for the game to throw something at me like the nurse-things in sys shock 2 - they ALWAYS freaked me out.
SPOILERS