Microsoft Sudoku

You can earn ONE Bronze badge per month. In order to earn the Bronze Badge you must earn 2000 coins during the month. You do this by completing daily challenges. New Challenges are added each day until the last day of the month. You can go back and play challenges from previous days, but only challenges marked on the calendar for the current month.

The earliest this Achievement can be legitimately earned is May 2015.

NOTE: According to BROOKER 513, this solution does not work on a SURFACE 2 running Windows 8.1. I used this running Windows 10 in a Virtual Machine and on a standard home-built desktop. So it may only work in Windows 10. If you try this on your Windows 8 machine, please comment below as to whether or not it worked.

Just wanted to add to what the two other guides have said. I have found that you can change the date on your computer to go back to previous months. Once you get a bronze medal in a previous month, change your date back to the current day, and you will see you have all of your medals plus the medal for the month you just got with the date change.

To clarify, here is an example. I have two bronzes for February, and March. Change the date on your computer to January 18th (or any other day relatively far into the month) and then boot up the game. Do enough dailies to get a bronze medal then quit out of the game. Change your date back to the appropriate day then load the game back up. If you check which medals you have you will see that January is now among your earned medals.

I hope this helps. Please let me know if I can clarify the solution in the comments.