You can't get any gamerscore (g) from Halo Waypoint. The only things that can be got from Waypoint are avatar awards such as armour for your avatar.
Halo 3 itself does not contain Avatar Awards, but you can download the free "game" Halo Waypoint off of the Xbox LIVE Marketplace. This "game" will count up your achievements and depending on which ones you've unlocked, it will give you Halo themed Avatar Awards.
you get all the vidmaster achievements on halo 3 and halo 3 odst
Halo 3, Halo wars, Halo 3:ODST and Halo:Reach
ODST Avatar armour can be obtained by 1. Owning Halo ODST2. Unlocking the ODST achievement 'Good Samaritan' (don't kill any engineers)3. Downloading Halo Waypoint4. Updating carier milestone5. Bleep-Bloop! Avatar Awards Unlocked6. Go to Avatar Creator and Select Awards7. Equip ODST Armour
Unlock Halo 3:ODST's Campaign Complete Achievement. Once you beat the ODST campaign, visit Halo Waypoint on the dashboard to unlock the item.
The names of all the Halo games are (in order): Halo: Combat Evolved, Halo 2, Halo 3, Halo Wars, Halo 3 ODST, Halo Reach, Halo: Combat Evolved Anniversary, and Halo 4. In chronological order: Halo: Wars Halo: Reach Halo: Combat Evolved/Anniversary Halo 2 Halo 3: ODST Halo 3 Halo 4
All in halo 3 and all in Halo 3 ODST.
the recon helmet for halo 3 is unlocked by completing all of the vidmaster challenges in halo 3 and halo odst
No all 1000 need to be on halo 3
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.
http://hubpages.com/hub/Halo-3-Armor