In order to unlock all of the Halo 3 maps you must purchase them from the halo 3 marketplace... heroic map pack is free, cold storage is free, and legendary map pack is about 600 live points...
You unlock each mission, pass the mission, which unlocks that section
You need to buy all the maps available before you can play Team Snipers.
yes and no. You can play all the maps in the halo 3, but you have to download the rest.
By getting halo 3 odst ( two discs ) first disc halo 3 odst campaign and 2nd disc halo 3 mythic comes with all the halo 3 maps.
Yep i got them all, if you buy Halo 3 ODST you get them all including the other mythic maps
Your work for them.
All in halo 3 and all in Halo 3 ODST.
There isn't a known cheat code for this on Halo 3.
There really isn't Halo 3 cheats except for manually done cheats from the controller itself. This cheat is a way of holding down your gun like master chief in one of the Halo 3 posters. If talking about like " type in this cheat and you unlock all the maps cheat" well no. There are no cheats like that for Halo 3. :)
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
if you mean to "unlock" them...no. You have to purchase and download those maps. They simply arent on the game disc and need to be installed on the hard drive. You also could buy ODST, and that includes a second game disc that has everything Halo 3: Multiplayer on it.<-----thats they best deal, plus you get Halo: Reach multiplayer beta
If by "halo 3 maps" you mean the Halo 3 Heroic, Legendary, Mythic and Cold Storage maps, then yes. However to play campaign levels, you must actually advance in the game to get to them.
go to http://hubpages.com/hub/Halo-3-Armor