Ain't this "already owned" logic broken anyway?

No, worked perfectly for me. I bought 17 mystery games and never got a single game I didn't own.
It's not 100% guaranteed because there might be limited quantities of some games, but it works correctly.

There was a hiccup the first day as it started, but after that, it seemed to be working fine. After the "mystery game" debacle of day 1, that evening, and with the 2nd and 3rd batches, I received no duplicates until I had exhausted the pools.

Wow, thats nice!
Then, it might indeed happen as you wrote...
Then its either "get a game you already own as a gift", or "attach a game which you may not like to your account" =)

I personally wanted SimCity 4, but just looking at the posts here - I probably did right by ignoring. I took a chance once and it was not exactly my thing.

...The whole point is to take a chance. Why on God's green earth would you EXPECT to get a amazing value game? Its a fun little mechanic for those who want to support GoG. I just did it once out of curiosity.

because of Good Old Games =)

Never heard of MaGog before. I did a quick google gives me biblical and other references then I realised I was stupid not to search for the term in the forums

http://www.gog.com/forum/general/magog_a_search_engine_for_gog_games/?search=MaGog

I'll try it out next time I have a code to give away. Though if it takes too long to work out the right syntax to find a wish listed game I might give up as time is more precious than money.

MaGOG is over here. And select Title as filter, type the game's name (or a partial one), and make sure "Wishlisted/Ungiftable" is selected below. Note that MaGOG only searches the public wishlists of users who specifically allow it.

Thanks for that. I'll give it a try next time I have a surplus game, or just want to send messages of disdain to people who have wish listed terrible games ;P

A quick question to all the refunders out there: how long did it take for you to get your money back? I sent a support ticket on Sunday afternoon, since the mystery game I got didn't show up on my account. Never heard back.

Sent another ticket since I can't redeem a gift code I got (it asks me to enter a reCaptcha, reCaptcha is Google, Google gets blocked by the Chinese gubnint). I asked them to add that game to my account. After all, I provided a valid gift code and proved that I'm not a bot. The answer I received was "Can't help you, ask a friend to redeem it for you." (!!!)

I received prompt attention during the sale, with the credits coming within 24 hours in both cases. The first request was conversions to gift codes, and the second returns for store credit. Not sure how much GOG can do to circumvent the Great Firewall, since that blocks a lot of things with extreme prejudice.

It's not like I'm asking them to do anything that would require any Firewall-circumventing prowess, at least not on their part. They'd just need to add two games to my account - one mystery which I paid for and which never materialised into an actual game (which is a website glitch) and one gift code I can't redeem because of Great Firewall-fuckery. I mean, adding and subtracting games from accounts should be a simple enough task for support, right?

That part, yes. My comment regarding blocking was more to do with the Captcha issues. You might want to ping them with a follow-up about the games, the request might have fallen off the radar now that the sale is over.

I did that earlier today, since not getting a reply on issues like that for over 48 hours seemed quite unusual. Still waiting to hear back from them.

If I hear back from them, I hope it'll be more helpful than the "advice" I was given by support to have a friend redeem a gift code for me. Like, should I give some buddy of mine unrestricted access to my gog account? I know Christmas is a time for sharing and all, but...