Shadow of the Ninja/Secrets

Hidden items
Each secret is an invisible box with a bonus inside. When you hit the invisible container, you will hear a sound. Three hits is enough to get the bonus. If you used ninpo, it will deal damage to all enemies and containers as well, revealing the hidden item.

Stage 1-1: katana
When you jump from the high block, you will see the box (kusarigama inside) and a monkey below. It seems like there is no reason to jump down, but actually there’s one. Jump down, get rid of the monkey and walk all the way to the right. Invisible box with katana is in the corner below the railing.

Stage 1-3: bombs
See the fifth big wheel? That’s the very first big wheel right after dual wheels. There are bombs right in the center of it.

Stage 1-3: scroll
You need the eighth wheel. That’s a wheel with two platforms. It locates in the middle of the screen; no parts of it are hidden up or below the screen. The secret is right in the middle of the wheel.

It’s no so easy to get it, however. First of all, get rid of the sniper on the right, or he will interfere you, dramatically reducing your chances to get the secret. You need to jump on the platform and hit the invisible box without falling down, but that’s only a half of the problem. The scroll falls down even through the platform and disappears below the screen, so you need to be quick to grab it. You can sacrifice part of your stamina and use ninpo, but your timing still needs to be good.

If your weapon’s level is 3, you don’t need this bonus. Just ignore it.

Level 3: bombs
As soon as you finish climbing ladders for the first time on this level, don’t move forward. The secret is left of the ladder, next to the top of it. Just climb down a little and strike left. You’ll get bombs.

Level 3: healing potion
The secret bonus is right before the boss. After the third (and final) set of ladders move right until you see the box with katana. Climb down. The container with healing potion will be near the right wall.

Stage 4-1: bombs
When you’re climbing up under the heavy fire of enemy mortars, pay attention to the satellite dishes. Hidden bombs are in the middle of the third one.