Star Ninja is a physics based puzzle game where the object is to kill all the pirates in each level. You play as a ninja that cannot move but can throw deadly ninja stars. You aim your shot with a cursor and the throwing star will travel in a direct line until it hits an obstacle. Most obstacles (including the edges of the screen) will cause the star to ricochet off in a mirrored direction, so you'll need to aim carefully to hit as many pirates as possible with each shot. Some objects result in the star becoming embedded in them stopping it's movement entirely, however they react to the force of the shot and can be used to knock into or onto pirates thus taking them out that way. There's also the odd bottle of rum lying around which, when hit, will explode causing any nearby objects to go flying off in different directions.
This core gameplay mechanic may sound fairly simple but, due to some clever level designs, it provides enough variety to stay entertaining for the entire duration of the game. In the main Focus Mode you receive a score at the end of each level based on how long you took and how many stars you threw to clear it, which encourages replaying the game to improve your performances. There are 3 other modes to play, each with slight variations to the scoring rules, but they all use the same levels as far as I can tell.
The graphics are clear and colorful with a cartoonish look to them, and the sound is great, with plenty of amusing chatter from the pirates. The physics work well, with shots and objects reacting in a predictable manner.
Star Ninja is a lot of fun to play. Sending several pirates flying in a single shot is immensely satisfying, and you'll often find yourself re-trying levels just to try a different approach or in an attempt to beat your score.