I haven't finished the game, yet: I think I'm 70-80% through it. Keeping that in mind... and keeping in mind the fact that System Shock II (SS2) is in my top three...
"Does it deserve a perfect score?"
Well, putting aside the fact that there shouldn't be such a thing as a perfect score - or even a score - no, it doesn't. So far.
It is a very good game. The presentation is incredible, the gameplay is relatively deep, the balance feels pretty good...
But I can't ignore the flaws. Here are the ones I noticed so far, in ascending importance:
The level design is... mediocre. I mean, it looks good, but if you compare these levels to SS2, you'll see that they are inferior. SS2 used corridors, large chambers, and lots and lots of side rooms. This game uses all of these things as well, except it's linear. You don't walk down a hall and duck into all the side rooms. You move from point A to point B. Occasionally there will be a major side route to pick up a specific item, but it's not the same as having a dozen suites lining the corridor. In my opinion, this makes the game world feel very transparent.
The enemy is design is... mediocre. So far, their best enemy design is the big daddy, and in all honesty, he's not cool enough to hold the entire game up on his own. All the other enemies are zombies with various kinds of weapons. There's a really boring teleporting zombie, too. Ooh.
The game is not fucking scary. At all. I was a little worried initially, but then I fought my first big daddy and got my ass killed. There is absolutely zero penalty for death, which means the tension went away. I got in the habit of resigning myself to multiple deaths per big daddy - that's not the way a scary game works.
Lastly, the writing is mediocre. While the method of presenting the writing (journals) is excellent, and the voice acting is excellent, the writing itself is horrifyingly flabby. It slobbers its way through whatever the local plot is, painfully landing on every point that needs to be made, and never wandering. The first one or two journals I find in an area are interesting, but the next fifteen keep hitting the same plot at a positively slothlike pace, making sure nothing goes unexplained.
The actual radio communications are also rather clumsily timed. It's too pat, too unrealistic.
Compare this to SS2, where the journals were fragmentary snippets on a dozen different plot lines. Nothing was fully explained, nothing was labored upon, the writing was lean and sharp. SHODAN's radio communications went on and on in a realistic manner - it gave the impression she was really paying attention to you, unlike the characters in Bioshock, who apparently only pay attention to you when you're about to do something momentous.
I know that a lot of people are going to be irritated by my review, but so far I haven't found the game to be worth a perfect. It's good, definitely play it. The fiction is interesting (although a rather painful farce), the world is well-defined... but I was a little disappointed.
How do you like it?