The Legend of Kage/Walkthrough

Forest
After the princess is whisked away, Kage lands at the base of the right side of the forest. The forest scrolls for a very long time to the left, but not forever. Eventually you will reach the end, and Kage cannot proceed any further. The only thing that will allow Kage to escape is to kill the Red Monk that maintains the curse over the forest. However, he will only show up when three Blue Monks have been defeated first. Each Monk occupies a portion of the forest. Kage must travel to the left, defeating any ninjas that get in his way or attempt to kill him. Kage does not have to remain on the ground. He can also leap into the air, or climb up the trunks of trees, in order to reach the tree tops and continue jumping. If the ninjas stop appearing, it is likely because a Blue Monk is in the region and is trying to attack Kage. Stop and fight the Monk whenever you get the chance, but watch out for his fire breath. If you simply run away from the Monk, you will have to return to fight him anyway in order to escape the level, so it's generally not worth running. If you kill all three Blue Monks by the time you reach the forest's edge, the Red Monk will show up to fight you. Shortly before you reach the end of the forest, you are likely to pass a single scroll on a tree trunk, mid-way off the ground.

NES version info: In the NES version, there is a ceiling to the forest. If Kage hits his head on the ceiling, he will immediately stop moving forward, and fall straight down to the ground. It is very useful to obtain at least one Orb before you fight the Red Monk. If you want to ensure your survival, try to kill a set of three red Ninjas in a single section of the forest until you find the red bonus face. Collect it to obtain the mirror illusion trick and continue to the end before your invincibility wears off.

Secret tunnel
To reach the castle, Kage must travel through a secret tunnel from the forest. He will be forced to roam through it continuously until he defeats 10 ninjas. A counter indicates the remaining number of ninjas before Kage can exit the tunnel. Kage can run along the ground, or drop down into the water. In the water, Kage cannot throw his shuriken, so he must use his sword to attack. As you run through the tunnel, you can see some Ninja's heads above water, while others are fully submerged, breathing through a reed straw. As you get close, they jump out to attack. Try to destroy each ninja before they have a chance to attack you.

NES version info: Don't forget to attack seven blue ninjas with your sword only, in order to summon the blue face bonus, and collect it for an extra life.

Castle wall
There is only one goal for the Castle wall stage: Reach the top. An arrow at the bottom indicates which direction you must proceed. All you have to do is leap upwards continuously. Throughout the stage, ninjas will assault you and try to end your journey. As you continue to jump, you will reach higher levels to stand on. While you can press down to drop to lower levels, this is generally not recommended unless it's going to save Kage's life. Throwing shuriken in the general direction that you are jumping is a good way to stay ahead of any ninjas who might jump out to attack you at the last minute.

NES version info: You can find a single black ninja who is holding a ninja scroll. Attack him and collect the scroll for a brief reprieve and a nice boost to your score.

Castle interior
The castle interior consists of four floors, each separated by a winding staircase. You must traverse across each floor, from one end to the stair case at the other. You can climb columns, or jump to other walk-ways along the wall. This is one of the most dangerous levels since you are extremely vulnerable to attack when you are climbing the stairs. You will face a mixture of ninjas and monks. It is actually safer to climb the stairs when there's a monk around, since he will only blow his breath weapon straight, instead of at an angle like the ninja. Timing your trip up the stairs can be tricky, but all you must do is walk forward to climb the stairs. Once you reach the top floor, you will be assailed by a never ending supply of Red Monks. Don't bother attacking one unless they get in your way. Eventually, you will encounter the princess, tied to a column. Use your sword to free the princess. As soon as you do, the game will enter a brief cinematic where Kage and the Princess leap to the roof and jump off to the forest below. However, the Princess will be captured once more and you will be forced into a confrontation with the level boss.

Showdown
After you rescue the princess, you will be prevented from making your escape by the level boss. You will either fight the dual knife wielding ninja Kiri, or the Samurai-turned-Warlord (or in the NES version, the Twin White Monks). The fight will be difficult since they can deflect most of your attacks. You will need to find a chance to attack them from a different angle, while avoiding their attack. If one of them gets too close to you, use your sword to deflect any potential attack.

NES version info: Don't forget that you must strike the butterfly five times before the boss enemy will become vulnerable to your attack.