BADASS !
Ninja action is the best part of this story
As the champion of an unnamed ninja clan, the shadowy protagonist you play as is gifted with mystical marks (insane yet classic Japanese full back/sleeve tattoos), which in addition to granting him some ninja-like abilities (namely speed and foresight) also slowly drive him insane. To combat this, the champion is honor bound to kill himself once his mission is complete. Beginning on a night when the ninja's clan is attacked by the personal security force of a powerful business tycoon, the champion is set on a course that will only end upon that tycoon's demise. Naturally, things complicate appropriately.
Story beats are delivered in short cut-scenes, but the majority of the narrative plays out during the player controlled action through enemy communications and a shadowy female ninja that pops in with quick observations (she serves as the verbal tutorial whenever new concepts are introduced).
As a narrative, the story works well as a back drop to the action, serving it's purpose in driving you forward. It falls apart in it's ending though, the quick (10-15sec) cut-scene following offers very little payoff if any to the enormity of the choice that the player is given.
While the story is passable, it's the environment and responsive controls that really steal the show. In bringing the stealth genre to the 2D level, the game designers have put everything you need to succeed on the screen in front of you.
Reminding me of Batman:The Animated Series, many of the beginning environments look like they were drawn on black paper, as everything carries with it a darkness that forms the basis of the stealth element. Even later levels (which shift the focus from cityscapes to Uncharted-like sandy ruins), while brighter environment-wise, still seem to come from dark starting points, as if it was this underlying darkness that allowed the ninja to exist and thrive in the first place.
The stealth system builds on this, coloring your ninja in when he's in the light and visible, leaving him as a combination white/red outline when he is indistinguishable from the world around him. Guards are given a clearly visible vision cone, which means that as long as you are in the dark, you know exactly how close you can get without having to guess at whether or not they will see you. Sounds are displayed in a bubble around the objects/people making them, leaving nothing to the imagination as to whether or not someone will here something. Eventually, one of the ninja marks you earn gives you "foresight", allowing you to look at the world around you in an infrared spectrum, revealing enemies you might not see, or even which device a switch might activate.
As Ra's Al'Ghul taught us in Batman Begins, being a hunter of the shadows is not solely based on invisibility, but also theatricality and deception. Your ninja is able to manipulate the environment around him, using a variety of tools (some unlocked through level progression, others through a point-buy system) to distract and, in some cases, eliminate his opponents. Bamboo Darts, given to you early on, prove to be the backbone of your arsenal, destroying lights that could potentially expose you, or creating sounds to draw guards either from your position, or into a trap of your making.
Using these systems to stay invisible and ahead of the guards is the best part of MotN. Scaling nearly every wall available, scampering through vents and under walkways, hanging from the ceiling, or shooting across the screen on grapple lines, every move feels tight and responsive. I never felt that the game asked me to do anything impossible, and when I messed up (which I did often while trying to push things to fast) it was always because I messed up, not the game.
On top of all the movement options is a world class stealth kill system, which eventually allows you to strike from nearly every position attainable. Striking while stealth is not only more enjoyable, but preferable, because while some advanced skills allow you to deal with enemies who are aware of your presence (a slide maneuver is particularly useful), simply wading into combat will more likely lead you to your last checkpoint then all-out blood-soaked victory. Using those same systems, however, being spotted is not hard to come back from (though I found myself often jumping back to the last checkpoint when this happened, severely disappointed that my actions revealed my presence)
Success in MotN is measured in points, as nearly everything you do in regards to moving/dispatching enemies in the environment has a point value associated with it, and their is a tally at the end of a level telling you how you did, giving you additional points based on how many times you were undetected by guards (passing by them while stealth), whether or not you set off any alarms, and whether or not you finished the level without killing someone (95% of the levels are able to be done without killing anyone). Each level has a three-rank point total to work towards.
Along with the point system, each level has three seals to unlock and three scrolls to find. The seals are like mini-achievements for the level (ex. Kill 6 of the couriers guards, Get sniffed by three dogs, Kill someone without being detected), and none of them ever feel cheap or impossible. Successfully doing these optional objectives unlock different ninja outfits that have a variety of +/- bonuses attached to them (my two favorite being Path of the Hunter, which allows your stealth kills to automatically succeed, and Path of Silence, which removes your sword, but gives you two distraction items, removes the sound of running, and a wicked almost solid black costume). The three scrolls found in every level are all haiku, and each share a bit of the back story.
When combined with the point total, each level beaten can grant you a total of nine upgrade points which can be spent on new stealth moves and character techniques (faster lock-picking, more health), new distraction items (including a cardboard box to hide in...), and new offensive items (Spike traps, Terror Darts!!!, Caltrops and those people eating beetles from The Mummy films).
With Mark of the Ninja, Klei has taken the stealth genre to new heights. With all the information required to traverse the world as an unseen specter (of death?) provided upfront, being a true ninja has never been more fun. No challenge ever seems impossible, no situation unbeatable (even when they take away a number of your information systems in New Game +). Do yourself a favor. Buy this game.