Can you still get achievements on Halo 3 if you use the Halo 3 mythic disc

[CrimsonBird5]

that you get with ODST? Just wondering because if it is yes i am trading in Halo 3 before i get ODST

 

[mr_j526]

Yes, anything that you can get in Halo 3 without the campaign can be gotten in Halo 3 Mythic. I'd recommend getting every last part out of the Halo 3 Campaign if you haven't already, before you trade it in.