I already have Darksider 1, Can i Enter? Thanks.

抱歉,steamgift規定是不能的喔!

他的意思是說由giveaway creator做最終的決定

FAQ: "What are the rules for entering to win Steam packs if I currently own a number of the games contained within?"

We ask users not to enter giveaways for packages if they already own the majority of the games. This allows for winners that will receive the most value out of their gift. In the end, the giveaway creator has the final say, and if they believe the winner owns too many of the packaged games, we'll allow them to request a new winner.

官方要求使用者不要,但是,最終決定由捐贈者說了算(如果你覺得winner得到這包太多遊戲的話,官方允許重抽)

ps:我之前有遇到大多都可以,所以還是由您做決定

Thanks :D