Took me a while to get used to it. Although the concept of crawling in the shadows and stabbing an unsuspecting Nazi in the spleen is oddly satisfying, the game completely collapses onto itself as soon as you are spotted and suddenly need to be a competent fighter.
As such, the game suffers from three major flaws:
First, the "slit a dude's major artery" button is the "A" button. Whenever you're close enough to a bad guy who hasn't seen you, pressing "A" instant-kills the bastard, one-shot. But what does the "A" button does if you've been spotted? Nothing. Absolutely nothing at all. So if you're a fraction of a second away from bringing down a Nazi, and you're spotted, "A" will not do pull out your knife and at least attempt a slash, it'll do nothing. To use a brain-wiring analogy, it would be as though you were an expert knife fighter, but only with your right hand, and if you wanted to assassinate someone, you had to do it with your left hand. Makes no sense. This is made even worst by the fact that what triggers the shutdown of the "A" button is the beginning of the enemy's surprise. So you can be one centimeter away from his throat, and 1/100th of a second away from ending his life, suddenly your attack button does nothing. In real life, the dude would still die, he would just die a bit more surprised.
Second, once surprise is gone, you have to activate the horribly clunky trigger-based fighting controls. This joke-of-a-system turns your expert assassin into a bumbling, drunken, marksmanship-deprived idiot. Throughout their evolution console-based shooters have evolved several compensation mechanisms to counter the fact that controllers are awful when it comes to precision and aiming. Velvet Assassin ignores all of that and gives you raw unassisted aiming. The argument for making manual aiming/fighting clunky and bad in stealth action games is generally based upon the fact that if you play your game well, you're never supposed to resort to that. You're an expert stealth killer, not front line grunt. In a way I could forgive this if not for the third and final flaw : no stealth in the final battle.
For the final battle, the designers decided to throw out everything that was good in their game and focus exclusively on what sucked: the no-stealth battles. Made artificially difficult, not by its design but by the horridness of the controls, the final waves of enemies produce an endless exercise in frustration. Oh and you can't go back and grind to level up your stats.
Velvet Assassin isn't such a bad game, and I would've left with a better experience had the ending just been sneaking up to a dude and slitting his throat, one-shot, rather than this. It's so annoying to give up on a game at the end. I find myself doing that more and more. But that's going to be part of an upcoming rant entitled "Games are too long".
Until then, rant-off.