Braussie: When you have a code with multiple games (like the PWYW Interplay bundle code) and you redeem it but already own some, the ones you own remain on that same code.
F4LL0UT: Oooh. I thought extra games only get preserved when buying a bundle directly for an account, not when using a gift code. Well, good to know.
Just chiming to confirm that Braussie is right ;)
So, perhaps you'll got several winners for this giveaway... :D
Happened to me in one of my giveaways: a code with 5 games of the first tier was for three different winners.
(the first winner took three games he didn't own, the second winner wanted to pick only one of the two left, and then I did a draw to choose the third winner among the participants who own already the game preferred for the second winner but not the other).