Uploaded September 2016 | Updated September 2026, 3 hours ago

---

Metroid: Other M's Nightmare boss fight happens twice, once before and once after Gravity Suit. While it's known that the second fight (Nightmare II) can easily be one-cycled, the first fight (Nightmare I) has been stuck at three cycles due to the cycle break points. However, it's been figured out that we can actually cut out a cycle through a few tricks. ((Note that a bunch of technical stuff may be slightly incorrect, as I don't have the game's code sitting in front of me nor would I be able to read it if it was, but the theories behind it are actually true.))


The first cycle lasts until around half health; I believe the first break point is 8 health, after which you can deliver one more attack before the fight transitions to the next cycle. (For purposes of this explanation, Nightmare starts with 12 health, supers do 2 and normal missiles do 1. While these numbers may not be correct, their ratio is accurate for this fight)
By firing a super, then a normal missile, we're still above this 8/12 level and can thus fire two more supers. The first brings Nightmare to 7, and the next to 5, transitioning the fight to the second cycle.

This is not enough to two-cycle the fight by itself, as the next break point is after two hits (I believe of any kind), at which point the fight transitions to the third cycle. Normally, we have no way to beat this transition. The most we can do is a super, which does 2. We can't take Nightmare from 5 to 0 in two attacks. However, coupled with extra damage from the first cycle, we can do it in three. And thanks to rapid-fire missiles, we can squeeze in a third attack during the second cycle.

By doing two supers, then rapid-firing a missile, we can fire off the third attack before our second attack hits Nightmare and triggers the transition, thus skipping the third cycle completely. The second super will hit Nightmare, bringing it to 1 and triggering the transition, and during this transition the missile that was already fired will hit Nightmare and kill it.


Long story short: Two-cycle fight starts with a super, then a missile, then two supers, all in cycle 1, taking Nightmare from 12 to 5 and moving to cycle 2. Cycle 2 consists of two supers and a rapid-fired missile to take Nightmare from 5 to 0. Technical aspects may be incorrect, theories behind everything are correct.