Shadow of the Ninja/Air Fortress

Stage 4-1
Move up, and two shooting troopers will appear. Destroy them and climb further. The next trooper guards the box with the sword. Each of the next three platforms contains one trooper. You’ll reach the aerocarrier. The cannon is on the right, and container with shurikens is on the left (pretty useful weapon against cannons). Climb up and reach the trooper on the deck.

Move right and fight different enemies. Here’s their list in appearing order: jumping trooper, trooper x2, jumping trooper, trooper, jumping trooper x2. Better get rid of troopers (especially not jumping ones). They are pretty annoying, and it’s very hard to jump over them without receiving damage. If you decide to run away from jumping troopers, better not stop. There will be a container with kusarigama, and a trooper right after it. When you jump down, all jumping troopers will very likely lose you.

The next part is pretty straightforward. There will be five cannons. The box with bombs is on the left of the sixth cannon, and the box with healing potion is on the right of it. There will be four cannons later, that’s a dozen in total. The exit of this stage is guarded by a shooting trooper, but he won’t cause you much trouble.

Stage 4-2
There are a lot of mechanisms inside the aerocarrier. First of all meet the line of three giant cogs and conveyers. Don’t even think about destroying cogs – it’s useless.

When you climb up, you’ll encounter wind ninja and find a box with shurikens later. You’ll see two giant cogs and another wind ninja when you’ll be climbing down. Get rid of him before he comes to the left side of the screen, or dealing with him will be much harder.

Move right. When you come to a platform and a glass window above, climb up. Katana on the left, kusarigama on the right. Pick up any weapon you like and climb down. Deal with another wind ninja and get ready for action.

Jump on the first platform and ride it up. Move to the next platform and ride it down. Romblast will appear right in front of you. It has a huge amount of health, so don’t even think about fighting it. Better move back and wait for the right moment to move forward.

Jump further over the platforms until you see two containers. The upper one contains shurikens, the lower one bombs. Move forward until you reach conveyor, get prepared. Romblast will appear. You can either try to get past it or you can try to destroy it with shurikens and bombs (don’t even think about destroying it without consumable weapons).

Move forward, meet another romblast. Soon you’ll see a niche with two floors. There’s a wind ninja on the upper one and a box with kusarigama on the lower one. It’s pretty easy to get there but not so easy to get out of there. Anyway, if you fall down, you’ll appear on the very top floor where you need to go. There will be a blue platform soon. If you stand on it, it will slowly move down, or it will move up in any other case. So if you need this platform to move up, just crouch on it or hang from it (or just rapidly jump). Get past the romblast that’s blocking the way. Soon you will encounter two rows of blue platforms. To the left of them (and to the right of romblast) is a niche with bombs.

Move forward, meet two wind ninjas and get to the elevator that will take you to the boss.

Stage 4-3
Capt. Hawk will be waiting for you here. Beat him to get to the last level of the game.