It seems like Walmart is collaborating with microsoft while promoting the snacks, and they are sending tons of downloading codes to all participants.
Here is how the promotion program works:
1.go to the promotion link below, and click "enter your codes"
2. in bag1, enter 373315XXX and 12:18, where XXX can be any 3 random digits you like
3. in bag2, enter 373315XXX and 09:39
4. enter any post code in the US (just google it)
5. enter your email address and date of birth
6. after everything is filled, complete the puzzle at the right bottom of the page
7. then click submit, go check your email box and you will be able to receive a download code
I got it at my first attempt, good luck and enjoy this game.