Some key players just won't die, no matter how many times you beat, zap, or shoot them. The world seems to stop while you're talking with people or 'inside' a computer terminal you've just hacked. Even if that gun was shooting at you before, or there's a bad guy standing 5 feet from you, they're going to stop and wait patiently while you finish your conversation or disable some important equipment. Ladders have always blown in FPS games. Ladders blow in Deus Ex.
Music ranges from good to excellent.
You'll always know when you've been seen because the moody music turns into jumpy action music. Then you'll know you're safe when the music returns to moody. Unless you've died at some point during the transition, then you get a lovely dirge played for you as you hover over what's left of your body. I like EMP grenades. This game needs more EMP grenades, but that's just my opinion.