for Chirstmas I got Professor Layton Miracle Mask which ment I could get that free donkey kong game but it said it may take weeks and the offer ends soon so my question is will I still get the code and be able to redeem it even after the offer is over or will Club Nintendo troll me?

if you enter it before the end date you'll get a code

1. If you don't have a club nintendo account already, make one.
2. If, and only if you have the digital download, you should get a survey about the game and why you purchased it on the nintendo e-shop within a few minutes to hours of purchase.
3. Wait for approximately 3 or 4 weeks after 2 and you should obtain an e-mail with the download code to get your game.
Step 3 should happen regardless of the time after the offer ends, but you need 1 and 2 done during it.

I'm wondering this too...

To the OP: It doesn't apply if you got the physical copy of the game — you have to download it to get the freebie.

I already had physical copies of Miracle Mask and Paper Mario so I ended up buying the Crossword Plus game digitally. It registered automatically about a day after I bought it and I'm now waiting for the e-mail code for Donkey Kong. If you have $30 to burn before the 6th and like crosswords, I would say get that if you want the free Donkey Kong game. I found myself playing Crosswords Plus more than my other 3DS games and Vita while away over the New Year's weekend.

thanks I was wondering what would happen after the little expiration date thing. :3

I didn't even get a Survey or a Code yet myself.

I talked with CS from Nintendo and they said too call within 1 - 2 Weeks if nothing happens, but I'd still like some extra help though.

Did anybody ever get a code?
I downloaded Paper Mario: Sticker Star back in November, filled out the survey, and have now been waiting for months. I must have missed something?

Did you create your account after downloading PM? If so, there's your problem.

If you downloaded one of the participating games a while ago, (A month and a half or longer) and never received a code, an error has happened. This has happened to me, when I didn't get my code for Downloading Miracle Mask.
Just call Nintendo's Toll Free Number and it should be changed with no trouble. They may need your 3DS Pin Code though. (The row of numbers on the back of your 3DS)