Purchasing BC2 Vietnam on Steam vs non-Steam
There seems to be some confusion regarding purchasing Vietnam. I hope this clears things up.
Any stores that "sell BC2 Vietnam", sell a 16-digit code. This code can be entered into the BC2 game client - any version of the game client. Entering this code unlocks Vietnam for that EA account. No additional download is necessary.
Here are some typical scenarios:
You have bought the base game on Steam, and Vietnam on Steam - this works. You will also see your purchase of Vietnam listed in your Steam client.
You have bought the base game on Steam, and Vietnam somewhere else - this works. The Vietnam expansion will not be visible in the Steam client, but you can access it in-game.
You have bought the base game somewhere else, and Vietnam somewhere else - this works.
You have bought the base game somewhere else, and Vietnam on Steam - this is not possible, because Steam will not sell Vietnam to someone who does not have the base game on Steam.
If you somehow did manage to make such a purchase anyway, please contact Steam support.
You have bought the base game on Steam, and someone has gifted you Vietnam on Steam - this works. You will also see Vietnam listed in your Steam client.
You have bought the base game somewhere else, and someone has gifted you Vietnam on Steam - I don't know yet what will happen in this case. Will update once I get that info.