NG2 6-1

Ninja Gaiden II: Act 6, Stage 1
6-1 is a short stage lots of enemy spawns and visual obstructions in the foreground. In any%, the goal is to obtain Art of the Fire Wheel and a Scroll, then reach the end of the stage with at least 8 Ninpo and with at least 8 HP remaining.

Foreground
Several parts of 6-1 have obstructing foreground graphics, probably to simulate the dark, vision-limited atmosphere of a cave. The foreground is drawn on top of all sprites, so enemy spawns and platform positions are very unpredictable for a new player. However, in a speedrun, the hazard is ineffective and not difficult to deal with, since you can just memorize the position and timing of everything in the stage regardless of being able to see it, as in Stage 3-1.

Room 1
In any%, traverse this room without taking damage. The first two item orbs contain a Purple Ninpo, of which you should collect at least one. Dispatch the Fire Bat that appears on the left with one of your Shadow Clones; the next orb reveals a spare Shadow Clone if you need it.

Room 2
Transition room. Note that you will always drop into this room facing right, so your left-wise movement is slowed until you hit the ground - unless you slash in mid-air before holding left to gain a short burst of speed.

Room 3
Boost off of the Bat by jumping early to force it to spawn higher up; the boost allows you to pass safely through the Demon and climb the stairs, dispatching the Alien Turret and collecting the Art of the Fire Wheel along the way. The foreground obstructs a platform in mid-air at this point; you can jump across it to reach a Scroll, but it is recommended that you fall to the ground and instead break the Item Orb with an Art of the Fire Wheel to get the Scroll..

At the next pit, which contains a Mortar, simply jump over it to get boosted by the Fire Bat from behind, assuming you haven't slowed down yet. This will pass you through the Mortar and Boulder Guy unscathed. At this point, a few Fire Bats, Flames, and Crackheads spawn, but a single Art of the Fire Wheel destroys everything (also dropping a spare Shadow Clone).

The next platform spawns a Flame. Unfortunately, some kind of sub-pixel RNG may be at work here, and sometimes the Flame cannot be passed without getting hit. While you don't slow down, expect the possibility of taking 2 damage here. Approaching the end of the stage, a Fire Bat spawns behind you and may hit you, dealing another 2 damage. If you're low on health, dispatch it with an Art of the Fire Wheel at the expense of a few frames. Remember, you need at least 8 HP entering Stage 6-2 if you want to make it to the boss.