Halo 3: ODST maps question...

Okay, so i know that all maps ship with odst but do they work with halo 3 also or can you just play them on odst's bonus disc? or is it that you can only play them on halo 3? im really confused. :|

Yea, why would they make achievements for Halo 3 that we can never obtain? We have achievements to get skulls on those 3 new ODST maps...so eventually they will be available. It has to be more complicated though, or else we could just rent ODST, beat it play the crap out of Firefight and then download the maps and return it. They might just end up selling the new maps for Halo 3 down the road, who knows.Mau-Justice

The second disc is merely the multiplayer executable portion of Halo 3 with the map packs on the disc. This means that you will be playing Halo 3 multiplayer from a multiplayer only disc running all of the maps directly from the disc as you would, say, valhalla on your original halo 3 disc.

Knowing Microsoft they may make you have to use ODST disc to play the new MP maps. MS may not want people to rent the game and pass it on to everyone to just download the maps to the HD.

If you read the hands on multiplayer preview, they specifically say:

"The aforementioned campaign and Firefight modes will come on one disc, while the competitive multiplayer comes on a separate disc within the same box. It's the same exact Halo 3 multiplayer fans have been playing for nearly two years now, but with every downloadable map pack ever released for the game on the disc. And, of course, there's also the trio of exclusive maps known as Heretic, Citadel, and Longshore."

Then why did they put these achievements on Halo 3...If you can't ever achieve them? There's also 3 others besides the ones below that involve accomplishing tasks on each of these levels.

Citadel Skull
On Citadel, find the hidden skull.

Heretic Skull
On Heretic, find the hidden skull.

Longshore Skull
On Longshore, find the hidden skull.