Two hit core X:
It's possible to have two Missiles inside of the Core X when it becomes vulnerable. That is, you can hit it twice on the first wave. This allows you to beat Serris's Core X, for example, in the time it takes it to become vulnerable four times (instead of the normal five).

Spider (A.K.A Yakuza)
Stand in the center of the room and fire straight upwards to take enough damage off of Yakuza to kill him the next time he opens his mouth. It is also possible to do this without getting hit.

Omega Metroid:
The final boss can be killed very quickly if you have a quick finger and good luck.
The middle of the three Ice Beam shots must hurt the Omega Metroid for this trick to work.

SA-X 2nd Form:
Defeat the normal form SA-X first, using a method of your liking. Then, as soon as it starts to transform, jump up onto the platform at the top left of the room. From here, just fire charged wave beam shots straight down.
The SA-X can't reach you, it will just mindlessly jump up and down directly below you, so you will never take a single point of damage, and it should die within just a few hits. :samus:

To watch footage of these tricks click:HERE You may need Quick Time 7 for some of these videos to upgrade to quick time 7 Click:HERE!