Just a little tip for you, once you've got your three registered games and you get a code for your fourth, free game, open a new club nintendo account and link your 3DS to that before you download the game and it'll count as one of the games in the promotion, getting you one step closer to another free game.|
Might be handy for some, I did it myself. Basically means you can get two free games if you have 5. You can only get one free game per club nintendo account so you'll need to open another anyway if you have a few.
Steam - iN5OMANiAC
PSN - iN5OMANiCAL