You have to earn achievements or get skulls.
they unlock cool stuff
Get some skulls dummy
Youtube
Get 1000 gamerscore for specifically Halo 3. You also unlock the Security Helmet.
get all the skulls easily u can you tube it also u can play multiplayer online to unlock items getting halo ODST u can unlock recon by doing the vidmaster challenges in halo odst and halo 3
No, in Halo 2 you can not unlock armor.
There are 13 campaign skulls ( 9 gold ones which unlock achievements and 4 silver ones which make the game more fun ) and 6 mythic skulls ( 3 for the halo 3 mythic pack and 3 more for the halo 3 odst mythic pack )
Sorry there arn't any, The only skulls are in "Halo 3" Which are used in "Halo 3 O.D.S.T."
Some of the Halo 3 skulls do stuff. I got the skulls so that I could unlock the Hayabusa Helmet. Turbo-117 They areskulls found on various parts of the map and can do things for instance the grunt birthday skull makes confetti appear from grunts when shot
When you collect all of the skulls in Halo 3 you get the awesome Hayabusa Armor that's the only Armor you unlock in Halo 3 by collecting skulls. Note that you can't collect the skulls on the Easy difficulty it has to be on Normal difficulty or higher and also note that I have found all 13 skulls and Bungie put them in Bizarre places I'd recommend going to the related link to find them especially the I Would've Been Your Daddy(IWBYD) skull it's the hardest to get.
you can get all of the skulls on multiplayer. =)