[IMG]http://i.imgur.com/QxfrNZC.png[/IMG] I didn't log in every day up til the 25th though... and since it's green, doesn't that mean I should get the prize? What's going on?

This problem was discussed in this thread:

Melody Regular 2013

What's happening is that the prize is only given if you visit Melody on every day from December 1 through 25. However, the counter you're seeing increments every time you visit, so the first achievement shows up as green if you visited for any 25 days in December, not just the first 25.

That's just dumb. XD But thanks for letting me know! :D

Make sure you visit all the way through the 31st next year. The achievements don't stop at Christmas.