Full Review

First of all, this game is called Ninja Five-O in US, so I don't know why they listed as Ninja Soldier here. No matter what the name is, this is a great side scroller that any fans of action game shouldn't miss.
In the game, you play as Joe Osugi, a ninja that has decided to supplement his ninjitsu skills by becoming a detective. The gameplay is typical of a side scroller, you move from left to right, until you reach the end of a level and defeated all enemies. What makes this game fun is the two added features to the game control, a grappling hook maneuver and a scan mode. Joe Osugi's grappling hook allows him to climb up and down, swing from side to side, to dodge enemy fires and explosive, or to reach areas that a normal jump wouldn't be able to. The scan mode is critical for you to beat the game, by holding the L-Button allows you to move the screen around your character’s viewing parameters, so you view where the enemies are, where there's a spot that you can land after the swing, ro to find keys and power ups to advance the level. These two features are subtle additions, but they sure improve the gameplay over other side scroller games.
The level designs are nothing to write home about, but each level all appeared very different than one another, and there are plenty of different enemies and hostages for you to kill and save. The music is very nicely done, it fits the retro feel of a 2D side scroller games, which were very popular back in the late 80's and early 90's. One thing I really like about the game is the cool ninja magic effects, they take the whole screen and really give you a "wow" factor when you use them.
If there's anything negative about the game, it's the difficulty level. This game is no push-over, if you've played the old Shinobi games, you will know what I'm talking about. The scan mode is a life saver, since a critical move and perfect timing is the combination to beat the later stages, no to mention collect the powerful power ups. Having only one auto save slot adds another notch to the difficulty level. Beyond this, this game is highly recommended for all action fans, it's shame that Konami didnt promote much of this game. This can be the release of the third Castlevania: Aria of Sorrow in few weeks. Nonetheless, this game is still worth and time and investment of any GBA owner.