General Multiplayer Tricks
From M2K2: Metroid Prime 2 Wiki
Discovered by
Ummeiko... and probably a few others
In levels with grapple hooks (Shooting Gallery and Sidehopper Station), you can reach the grapple hook (and therefore the upper level) by standing under them a little to the front/back, looking up, double jumping. This puts you just within grapple's reach, and is good for nabbing the super missiles that are under some of the grapple hooks or quickly sneaking to the upper level.
Posted by
Ummeiko (I can't really take credit since it's in the Players guide)
If you lay a morph ball bomb under an opponent, it will detonate immediately, instead of the normal delay that you have when laying a bomb.