For Halo 3:ODST, I have two questions. One: How do you get recon armor once you buy the game. Two: How does Firefight work, and will that be the only online play for ODST?

you get recon by compleating vidmaster challenges in halo ODST and halo 3

Halo 3 ODST
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-vidmaster challenge: classic - finish any level solo on legendary, on live, with no shous fired and no gernades thrown

-vidmaster challenge: deja vu - complete highway on 4-player lengendary LIVE co-op, with iron, and "no hog or scorpion"

-vidmaster challenge: endure - in firefight on any mission pass the 4th set on 4 player heroic LIVE co-op

halo 3
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-vidmaster challenge: annual - complete halo 3 on 4-player lengendary Live co-op,with iron, and everyone in ghosts

-vidmaster challenge: lightswitch - get to the rank of lieutenant in any playlist with the EXP progression system

-vidmaster challenge: 7 on 7 - enter into any playlist with 7 EXP on the seventh of the month

-vidmaster challenge: brainpan - find all hidden skulls on the mythic maps

i can help you with all except lightswitch, or 7 on 7

if you want my help then e-mail me at alexleach34@yahoo.com my gamertag is elidog

I believe you need to beat that campaign on legendary or get all the audiophiles. Im not sure but it usually is beating the campaign on legendary. As for the online play, you can play campaign online with other players as well. For firefight, all i can say is it is seemingly an endless onslaught of enemies. It works in sets, which are divided into rounds, which are then divided in waves. There are 5 waves in a round, 3 rounds in a set, and im unaware of how many sets there are. Each round, a skull is turned on to increase difficulty. Hope that helps.