It would be a good game if they didn't have so many bugs in their system that won't allow you to receive credit where credit is due forcing you to complete the same challenges over and over with no reward. You could log in every day but would only get credit for logging in every 4 out of 6 days, making the monthly calendar impossible to finish. These issues are known to the developer but they refuse to fix it, nor will they credit the player the rewards they've earned. A prime example of fraud.