The first game in the series so it is expected it will lack features and content of later games (you cannot move dead bodies for example) making this age a bit bad. I still had fun regardless.
Those who never played this series before, this is a stealth adventure with Ninjas. Sneaking up with enemies means you can kill them with one hit, but if you are spotted enemies put up a decent fight and combat isn't suitable for such action, making it not worth the effort most of the time.
You can climb building and high ledges with a grappling hook, which makes traveling and stealth more interesting, one of my favorite parts of the series. It also makes many levels really open feeling, giving you options of getting the mission done.