Originally Posted by bblcreator8790
Your friend is right, you would be better off just getting ODST. The second disc contains every Halo 3 multiplayer map and you play it off disc (no installing content/no DLC codes, so preowned editions are fine). You still need your Halo 3 disc for the campaign and those achievements, obviously, but you will be able to get all of the multiplayer achievements with the ODST second disc.
Ok, thx! Weird but who cares as long as i get the achievements.