Shadow of the Ninja 2

ninja is the most feared enemy back in old Japan. It is said that they can kill a general even if there are many soldiers guarding the general.  However, they are also said to be noble warriors as they are just doing their job.  There is nothing personal in what they are doing. The goal here is pass each level.  You need to collect a certain amount of gem in each level.  Of course, like a true ninja, you can’t be detected.  You need to avoid contact with anyone at all cost.  Once that you are detected then the whole mission is a failure.