Last update: Giveaway over, thanks to everyone who participated. You can still post here if you want to be in the group just for the heck of it. (No, there won't be anymore giveaways. :P)

UPDATE: Steam won't work, so I had to change everything. Please read below.

So... I still can't search users or invite them to the group. This means I have to change the whole thing. Alright, I have a REALLY bad feeling about this, but here goes...
In order to be invited to the private group, you must follow these instructions VERY CAREFULLY.

1. Comment on the Steamgifts thread.
2. Wait for me to reply.
3. IF you get a reply, follow the link to the group.
4. Post a comment in the comment section of the group.
5. I will send you an invite to the REAL private group.
6. Enter the giveaway, have fun.

Now, let's hope this works... :-/

And here we are! I bought a game to giveaway and was thinking of a good puzzle idea I could use... Well, I'm too lazy to think up something good as a puzzle. Instead, I'll just "borrow" an idea from a few users that I saw a while ago...

Do I Know You On Steamgifts? [GIVEAWAY]

So, how does this work?

Simple. If I know or recognize your Steamgifts name or profile picture, I'll invite you to a Steam group, where a giveaway for Super House of Dead Ninjas is ready and waiting.

Simply comment on the thread, and I'll check if I know or remember you. If I do, I'll reply to your comment and you should receive an invite to the Steam group.
Please feel free to let me know in the thread if you didn't receive your invite even if I replied to you.
Also, please don't insist if I don't remember you.

Giveaway ends in two days. Good luck and have fun!