"Center" has been said by many on the shooting range targets, but that is a bit misleading. You get the most points for centered head shots specifically. Maybe if you were to temporarily relocate your savegame, which would basically result in showing that challenge uncompleted, you could find whether it's still doable under the current patch. Personally I wouldn't do that though, as the game is already questionable as far as recognizing unlocks, so it's a risk. Part of what you said there makes no sense. Nothing in the prima guide for the game or even Eidos' verification of the necessary criteria on their official forum indicates anything about having to get Silent Assassin rating, which isn't even possible anyway via killing so many non target NPCs. As far as the civvies, look at that AoD thread and you will see people claiming they've done it via saving them, via letting them get killed, via being spotted by them or staying hidden from them. That tells me the civvies have no bearing on challenge success whatsoever. Anyways, I don't really give a crap about the game at this point because Eidos really dropped the ball. I used to bemoan them handing Batman over to Warner Bros, but at this point WB is looking a LOT better to me than Eidos. DE: HR wasn't nearly the game it could have been either.