I-Ninja puts you in the silent shoes of Ninja, a short, large-headed ninja in training. The story starts off as Ninja rescues...well attempts to rescue, his teacher, Sensei, from one of Odor's evil creatures. In the process, Ninja recovers what is known as a Rage Stone, and as he tries to assimilate this awesome power, he ends up killing his sensei. His teacher's ghost then rises up and explains that Ninja must collect all the rest of these stones so that he is powerful enough to stop the evil Odor and his Ranx army.
One of the best parts of this game is the fact that progress through it is completely reward based - in order to get into certain levels and beat certain bosses you need to have a certain belt color. You earn belts by completing levels and earning grades. Each belt takes more grades to reach then the previous - and there are a total of 64 grades to be won in the game.
As you complete levels, you also add money to your Ranx Bank and your Coinage Bank. Every time you fill your Ranx Bank, you earn a new and more powerful sword (one for each belt), and you collect Coinage in the levels so that you can buy tests from the ninja guardians that you free at the end of each location.
There are a total of five locations in I-Ninja. Robot Beach has you attempting to put together a giant robot in order to defend the island. These levels will eventually put you in control of a giant ball and 'Ninja Bowl' your way to the finish - this is basically an up close and insanely fast version of Marble Madness.
Bomb Bay is at the harbor where you must destroy the Ranx's weapons facility and keep their sea forces from invading the harbor. Jungle Falls has levels that reminded me of the classic Frogger, as well as levels where you have to guide missiles through corridors and around corners in order to hit targets. Then you must stop the evil army from stealing the clouds at the top of Mountain Gorge, and finally you will face the final challenge on the Moon Base.
Each location acts as a hub for the levels of that 'world'. If you are a high enough belt, you can enter the level. Upon completing the task, you will receive the grade. You can do each of these levels at most three times (each time you play it - the challenge gets harder so you need a higher belt to get in).
Every time you beat a boss in I-Ninja, you free one of the ninja guardians (who you can buy more tests from later). You also receive another Rage Stone. What's all the fuss about these rage stones, you ask? Well every time Ninja absorbs one, he gains another ability. The first stone (from the intro movie) gives him the Ninja Berserker ability - this gives him back some of his health and makes his attacks stronger.
Later, Ninja gets the Ninja Revive ability - this restores a set amount of Ninja's health - which is good because there is no health laying around in this game. All health lost is returned once you beat a level. Next is the Ninja Shuriken. This Rage Ability has Ninja flying around on a giant throwing star plowing through baddies.
The last -- and best -- is called I-Ninja (short for Iron Ninja). Simply activating this ability does damage to the opponents on the field - not to mention the increased attack power you have control of.
You can't just use these abilities whenever you want though. As you kill enemies or get hurt, each ability icon fills up (in the order listed above). Once an icon is filled, you can use its ability. One of the only gripes I have about this game is the fact that once you use an ability, all of your 'rage' is depleted. For instance, say I have all four abilities at my disposal, and all four icons are telling me I can use any one of them. If I were to choose Ninja Berserker (the first one that fills up - and thus the one that is lowest on the effectiveness totem pole), I would not be able to use any of the other abilities afterwards - until the appropriate amount filled up once again. I felt gypped when I realized this. I mean it didn't take that entire amount to fill up the Ninja Berserker - why should it use it all up.
The only other problem I had with I-Ninja was the fact that he can't run. That's right, this guy is training to be one of the greatest fighters and is setting out to destroy this evil army, and he can't run. He can walk fast - but nothing near a run. Let me tell you, in some of those timed levels - it would be real nice if Ninja could move just a little faster (course the designers would just shorten the time limit if that were the case).