The chaos system in it is rather nice, though I found it fluctuated a lot from high and low between missions so it mayde thing very random. From what I played in the game (and this was on the hardest difficulty), the stealth kills are not too hard as long as you use blink well. They do get harder to do larger on though,
|seeing as about half way through your basic enemy becomes assassins. Much harder to sneak up on and they can use the blink ability.|
Greyfeld has a good point about the dialog among the nameless NPCs, it happens a good few times and I missed it in chapter one. Meaning the poor bugger had to die. Though it also happens for things not mission related; things like where runes are, safe combinations (there seems to be a good number of safes in the game) and things like guard route etc.
If you go the kill route you get A LOT of weepers and rats, which can be a real pain as they never seem to be alone, always groups of you. Then if one detects you, another will, then there is a domino effect and you end up getting guards and tall boys after you. Oh the fun!
Tallboys are hard, they can detect you rather easily as they are high up. One arrow from them takes abut half health and they take alot of ammo to kill (unless you hit their 'weak spots' which I find hard to hit, then it is like two). A thing that I think that is worth mentioning is the 'heart,' and item the outside gives you.
|The heart, an item you equip, can be aimed at people and locations and when used will tell you secrets. This is cool for a number of reasons, gives you a lot more story and background on characters (be them major, or just the minor guard) and can be used to plan out how you carry out missions etc.|
Simply put, the game is amazing!