Every Skull, except the Blind and Assassins Skulls, are only available on Legendary difficulty.
source: http://halo.wikia.com/wiki/Halo_2_Skulls
You can play on any difficulty you just have to find them
you need to be playing on normal,heroic,legendary to find any skull on halo 3
You have to play on at least normal.
if it is the halo e.c It will say halo live update. halo update has a picture of legendary. like the one where you choose the difficulty on halo. two swords and a skull
No, Halo 2 is notoriously anti-homosexual.
On campaign on halo 3 (difficulty normal or above) by the river on the first level jutting out on a rock theres a skull.
There are not skulls in Halo 2! It's just Halo 3!
envy mode skull-its on delta halo on legendary
you have to beat it on all difficulty levels and obtain every hidden skull in the game.
If you don't start the level from the beginning the skull won't appear. If you did start from the beginning i don't know.
It depends on what you call beat. To Complete Halo you should complete All Campaign missions, Some people also may want to try it on harder difficulty levels. There are also some skull you could find
Play halo 4 no one gives a $hit about halo 2