Zelda Classic 2.50.2

[ZoriaRPG]

Nope, first collision takes priority every other weapon will just die as usual on collision except for ones that persist such as explosions.

That is what I would expect, and probably what is supposed to happen, but apparently not what Moosh experienced with simultaneous hits. I suspect that damage is calculated before the invincibility frames occur; and in some circumstances it can be applied from more than one source. In fact, I told him that the second collision shouldn't count, for just those reasons...but seemingly it can.

ZoriaRPG, I believe the first collision triggers Link's "invulnerability" phase, so the second fireball strikes and does nothing because Link is temporarily invincible.
EDIT: Since the projectiles on screen are indexed just like enemies, that would mean the first fireball created gets to do damage, then invulnerability is triggered and the second fireball does nothing. This is the same as hitting a bubble to evade an enemy attack--the 0 damage hit triggers invulnerability provided it has a lower index than the enemy attack (on a one frame double collision).

@CJC : That's always going to be true, because the hits do not occur in the same frame.

It's not that important, but at least I remembered to ask.
@Moosh Get your arse over here, and detail that problem you had with simultaneous collisions with your 'Death' enemy.