I got some too! : D Thanks Nintendo!!!

I assume it's with your friends, as you would be giving codes to your friends, but it doesn't specifically say..

"Here’s how it works:

- Use the code below to download the demo.
- Once downloaded, you can play the available dungeon with two friends* via local play. (Other modes such as single-player and download play won’t be available.)
- You can also try out online co-op mode during these hours:

10/16: 5 PM - 10 PM PT10/17: 5 PM - 10 PM PT10/18: 7 AM - 12 PM PT"

I think I'll hang onto my codes after the first day passes to see how it works then. I have some friends who are interested in playing but I don't know if they want to play at those selected times yet so it may be beneficial to give these codes to someone else...

After playing around with the demo, it seems like you can also play with strangers or just friends online. But now I'm wondering if you can meet up with one friend online and match with 1 stranger if you chose to play with friends.

 Double checked with the game again and you were right. Can only play with friends locally in this demo.

Oh cool, I got codes as well!

Guess I'll check it out once it's open.

I got codes, but I'll have to ask my college friends about it.

So how do i get the codes?

You have to be signed up for Nintendo's mailing list. I think I opted in back in the Club Nintendo days. Nowadays, I'm not sure where you sign up.

If I recall correctly, when you sign up and create a new NNID, it will also prompt you to add an email so I'm sure you can go about it that way, but not exactly sure... I also signed up with Club Nintendo, but there has to be alternatives :p

its only for USA it seems like

I don't know about Europe but I'm in Canada. So maybe it's a NoA demo.