From the XboxFocus.com Review:
When games are in development for a long time, high expectations are expected to come with it. It's these same expectations that can ruin a game, but usually, great games can overcome them. Dark Sector, a game that had its beginnings in 2004, has carried that same level of hype as it has pushed towards its release.
However, Dark Sector doesn't live up to the standard put upon itself. While the game is heavily influenced by some of my favorite games ever, such as Gears of War and Resident Evil 4, Dark Sector misses that video game magic (the only way I can put it really) that those games possessed. Whether it be numerous control problems, an unsatisfying multiplayer mode, or the fact the framerate is pops in and out throughout the course of the game, Dark Sector just doesn't have that "it" factor to put if above other action games. However, the game finds its own unique identity early on, and for the most part, can be solid gaming experience for those who are craving a single-player action game.