It's still not as creepy as I'd like it to be, but I have to give some kudos to the designers for making the growth in power and difficulty pretty transparent. I'm pretty well along in the game-- I think I may be on the last "level"-- and though I have some serious kickassery stuff happening, the critters that I'm running into are powerful as well so the challenge is still there.
Spider splicers suck. They're fast, they're tough, and they do damage. And there are a lot of them. The Big-ass big brothers to the little sisters are the toughest, and woe be unto you if they corner you, but I've found a handy-dandy trick that takes care of them quite nicely if the circumstances are right. And it's a perfectly legitimate bit of gameplay, not an exploit of the coding. As a matter of fact, I haven't really seen any serious bugs yet, or even run into possible exploits.
My only complaint would be that there are times when there's too much going on. When you've got a Bouncer on your ass, machine-gun turrets shooting you, and Spider Splicers raining down on your head, it's not the time to be listening to a tape.
The AI is pretty amazing. The enemies that you run into really react to what you do, and in a fairly realistic manner (well, realistic for an art-deco underwater city with highly advanced technology). There are times when you can hide from them, and some of them cooperate with each other against others. And it runs differently every time, it's not scripted stuff. Impressive.
I know I'm coming up on the final "boss battle", though they've done pretty well to keep that concept pretty low. I still have three Little Sisters to rescue or kill on this level, and they all have bouncers.
Still, recommended. It's a nicely designed game, and it's fun.