This is a fun game. Lots of ways to play the game, allowing it to be far from your mindless shoot-em-up. The story is really good. Lots of achievements and side stuff to do.
I have one HUGE gripe with it. It is very glitchy. Do NOT do what I did: attempt the no-seen, no-kill run. I did this. I got spotted by no one the story doesn't force you to get spotted by. I killed no one the story doesn't force you to kill. I put many hours into this. I got the end of the game. Guess what I got? Neither achievement. I read online that the quick save/load feature doesn't always reset those counters, leading you to falsely believe you are still on a successful run. It would have been nice to have some kind of something telling you if you are still on a pacifist, stealth run, but no. There is nothing. I am still mad about this and it has been years.
3.5