I managed to complete all daily and hidden challenges but I lost two points for late submissions of solutions of day 21 and 24. At the end I finished 15th with 93 points out of 95 possible. I am very happy with the result and as always I learned a lot!
Day 01: 5th anniversary
Day 02: Wishlist
Day 03: Strange Logcat Entry
Day 04: HoHoHo
Day 05: Only one hint
Day 06: Santa's journey
Day 07: I know ...
Day 08: True 1337s
Day 09: JSONion
Day 10: Just play the game
Day 11: Crypt-o-Math 2.0
Day 12: Giftlogistics
Day 13: Muffin_asm
Day 14: Happy Cryptmas
Day 15: Unsafe Gallery
Day 16: Try to escape ...
Day 17: Portable NotExecutable
Day 18: I want to play a Game (Reloaded)
Day 19: Cryptolocker Ransomware
Day 20: Linux malware
Day 21: Tamagotchi
Day 22: Frozen flag
Day 23: Only perl can parse Perl
Day 24: Chatterbox