Merry Gamer Christmas! - aka Post Which Games Have Christmas Specific Achievements!

Hey Guys!

First of all, Merry Christmas to all of you on SteamGifts!
But even though the holidays are here, we have games we like to play, and those games have achievements, and some of those achievements in some games are only unlockable during Christmas. Sooo why not help each other and list games which have Christmas specific achievements? :D
3 years ago Corinne have tried to do something like this (https://www.steamgifts.com/discussion/iE729/christmas-achievements-cave-story-costume-quest-psychonauts), but I want to involve you guys too, and make the initial list grow :)

I'll start:
Costume Quest - Tisn't the Season - Play Costume Quest on Christmas (Dec 25)
Serious Sam 3 BFE - Christmas in Cairo - Decorate the Christmas Tree with a Gnaar Eye, a Rocketeer Heart and a Kleer Skull on the First Map (Summer in Cairo)
Serious Sam 3 BFE - Reindeer Hunter - Decorate the Christmas Tree on ALL SS3BFE vanilla levels
Psychonauts - Christmas Shopping - Buy something from the Camp Store on Christmas
Cave Story+ - Merry Holiday Happy Euphemism - Play Cave Story+ during the Holidays
Hammerwatch - Merry Xmas 2013 - Collect 24 presents over any amount of games
Interstellar Marines - Xmayhem Terminator - Pick up the Gift to become the T-IM101 (Multiplayer only)
Interstellar Marines - Hasta La Vista, Baby! - Terminate the T-IM101 (Multiplayer Only)

User submissions:
thom22 - Coffin Dodgers - Christmas Truce? - Win a network game on Christmas Day
PMR - Dino D-Day - Santa's Little Helper - Collect 15 gifts on cp_snowypark in one match

REALLY SPECIAL ACHIEVEMENT!
Batman Arkham City GOTY - Storyteller - Go on 12 murderous dates with the Calendar Man Exact dates

These are all I know. If you know something I missed, feel free to comment :)
Happy achievement hunting and holidays!