Xecutionmas: Medium forest facility, metal Carol of the Bells
Tundra Temple: Small temple, dark clouds, dark music
Christmas Crates: Medium storage area, dark clouds, metal Jingle Bells
Christmas, in Space: Medium space base, snow, jazz Santa Claus Is Coming to Town
Cliffside Fortress: Large techbase, starry night, mountains, dark music
Slay Ride: Medium-small forest facility, Doom weapons w/ rocketjump, metal Jingle Bells
Gardens of Athena: Medium forest & void facility, ROTT God Rest Ye Merry Gentlemen
Ritual: Medium-large tropical/lava temple, starry night, dark music
Facility X-423: Medium-small burnt-out city facility, snow (nuclear winter?), mysterious music
Social: Large mountain techbase, day, cloudy mountains, snow, groovy music
Hearth's Warming Eve: Medium-large remote techbase, cloudy night, snow, trees, arcade music
Bloody Christmas: Large blood temple, clouds, ice, metal music
Ruinous: Medium-large brick & metal facility, cloudy, snow->lava, metal music