Excellent game so far.
One thing though: when Nema gets the "alarmed" perk that gives her stealth she stops being able to attack enemies, with no way to turn off the stealth or the perk. I ended up restarting the game just so she'd be useful again.
Those guys and their little followers can be hit by any attack, it's just about timing for them.
The + or - symbols next to your perfects don't effect your score, they just tell you how close you got to an absolute perfect hit. + means you hit it late, - means early. There's nothing special for getting a +0.00 perfect though, so don't fret too much about it.