An under-rated action game that falls just short of greatness.
Certainly an interesting premise, but action is the star of Oni. Konoko is capable of bringing a whole lot of pain to the party through a devastating selection of hand-to-hand maneuvers, ranging from simple punches and kicks to strings of combos and incredibly satisfying neck- and -back-breaking throws.
There are also the firearms to consider, including standard pistols and machine guns, as well as the more interesting (and useful) swarm-missile launchers and frozen-mercury firing rail-guns. One neat bit of gameplay that connects the melee combat with the firearms is that you are capable of stealing an enemy's weapon before you take them out (which will be invaluable in later levels). While the firearms are certainly necessary to completing the game, they don't provide quite the same level of achievement as when you take a guy down with a well-timed spinning jump-kick.
The controls in Oni are a little difficult to get used to and are uneditable in the game, although the commands are simply written to a text file and it may be possible to rebind them (I've never tried). But, once you do get used to the controls, you'll be beating down pretty much anything that crosses your path.
That being said, Oni is a difficult game. There are somewhere around 15 levels in Oni. During every one, you will be fighting a seemingly unending horde of well-armed villains. To break up the action there are some jumping puzzles and sneaking sections that are difficult because of Konoko's floaty-feeling jump, and your enemies' ridiculously good eyesight. Also, there are parts that will require multiple run-throughs due to the fact that there isn't a save system in Oni. The distance between the save points are overly long (like other more recent Bungie titles). And this can lead to a fairly high amount of frustration, that fortunately, due to the visceral martial arts combat of Oni, can be taken out on the unsuspecting minions in the game.
The graphics of Oni are average for their time but poor by today's standards. The sound effects and voice-acting however are both good even in comparison to some of today's titles. However, like nearly all PC games, Oni has retained absolutely none of its initial value in stores, and can be had for as little as $1.00 on eBay. For that price, Oni is a must-own title for third-person action fans, and a game that is absolutely begging for a sequel that takes advantage of the gameplay innovations of recent genre hits like the Prince of Persia series.
The bottom-line is that Oni is an under-rated action title that despite unoriginal and somewhat tedious level-design offers a fun fighting experience that should not be missed.