Simply the best rail shooter ever made.
Unfortunately, that claim isn't much unlike saying "The best rail drink ever made". Is it okay to be the best of the pedestrian?
Extraction is a "guided experience" meaning you're doing a whole lot of pointing and shooting, with no control over exploration or movement. Within those limitations, the game mostly succeeds. Relentless waves of enemies require careful use of the game's gears of war-like reload system, and, as in the hd big brother game, dismemberment. The often numerous waves of enemies create a frantic pace, but they're never really much of a challenge, even on a harder difficulty, and there's none of the ammo scarcity that horror games often use to create tension. Instead, it's more about crowd control and reloading properly. Tilting the wii remote for alt-fire is a nice touch, but makes aiming difficult.
I found the game's use of the first person to be absolutely brilliant. The game plays up your starting character as the lone surviving hero, not unlike Dead Space's protagonist. Moments later, a group of survivors mistakes you for one of the crazed, shooting you dead without warning. The promised hero crumples to the ground, and the game never wavers from the first person perspective.
Not many games have the guts to kill the player character, but Extraction does it with reckless abandon. This turns the usual "group of survivors escaping monsters" cliche on it's head; while not a death sentence, every character you take charge of is put in a very uncomfortable spotlight by that opening scene. The writers are brash about how they kill off their characters, and some excellent writing/acting cements your interest in these unfortunate, stranded individuals.
Dead Space Extraction is the perfect rental/$20 game. It's absolutely worth playing, if only for a late-game scene that will be experienced by far too few players, but never forgotten by those lucky enough to have played it. Tension stays high, and the look/feel of the original is captured to near-perfection on the less-capable WIi. It's also worth re-playing with a friend, but make sure you play solo the first time. Most might be too busy with the AAA right now for an only A-grade title like Extraction, but it's absolutely worth hooking up the Wii for.