a friend of mine compared this to "gears of war" when he recommended it to me. while he might be right about that when it comes to certain aspects of the look and the controls, i think it can't compare at all when it comes to story. with "gears of war", even though the story isn't exactly the pinnacle of storytelling either, you always have a feeling of how the plot constantly progresses. not so with "dark sector"... you run and run and run and then maybe there's a cutscene here or there. and some of those cutscenes don't even seem to be particularly relevant to the story.
but it looks great, it has nice features (although e.g. the weapons upgrading feels more like "well... it is in there" than something they really thought a lot about - feels a lot better in e.g. resident evil 4), hacking away at those monsters is a lot of fun, which is why i would still recommend it to action fans. just don't expect it to be a game that gets you hooked immediately until you finish it.8/10