Ninja Gaiden is the 1st game in the NES trilogy. It was made in 1989 by Tecmo, who also made Tecmo Super Bowl.

Graphics
Amazing graphics. Nice detail and animation

Sound
I like the sound effects a lot and the music, in my opinion, is the best in the NES library. Awesome beats, epic melody, nice use of the instruments and stage 4-2 is one of my favorite video game themes of all time.

Addictiveness
Fun slashing and throwing weapons at people especially with the awesome sound effects. Being able to jump wall to wall is unique and fun. The addictiveness score would be higher if the game was not so hard.

Story
The story starts when Ryu Hayabusa, the coolest ninja ever, goes to America so he can kill people to avenge his father's death. This beginning story makes it more fun and satisfying killing people (Or making them disappear.....)

Depth
This is one of the first games, if not, the first game to offer cutscenes. The game is a little long for a NES game with 22 stages (including bosses) but after beating it, there is nothing else to do in the game. There is only one difficulty. It did offer other weapons to collect though.

Difficulty
This is one of the hardest NES games worth playing. Enemies are fast and hard to hit, ammo for your weapons are scarce, the sword you start of with is short in range, there are lots pits, and you fly back when you get hit, increasing your chance of falling into pits (this is a even bigger problem than Castlevania). This game contains one of the hardest stages in video game history: stage 6-2. Also, in act 6, if you die in the final three bosses (stages 6-4, 6-5, and 6-6) they send you back to stage
6-1, making you do the incredibly hard stage 6-2 again. The bosses are very tough too.

Overall
One of the greatest NES games in my opinion. This game is very overlooked because of the difficulty. Sadly, beginners cannot share much of this game's greatness because of the difficulty too.