Whitemare 2 (WHITE2.WAD)

The Russian Doom Community has this thing they do on occasion where they build a megaWAD out of selections from assorted "freakmapping" speedmapping competitions, after tuning up some of the submissions and adding a few new ones. This gave us Heroes' Tales back in 2009 and Whitemare in 2011. Whitemare 2, released in 2014, is a full-fledged megaWAD for Doom II for Boom-compatible engines (specifically PrBoom+). This time, the demons decide to ruin Doomguy's New Year celebration by stealing winter, disrupting the normal progression of the seasons. Or, something like that. I think that Doomguy starts off by fighting off another demon invasion, with them absconding with winter and causing a skip right on through to spring. You rush off to rescue it, and succeed, only to find that something evil has snuck back with the season.

Whitemare (WHITEMAR.WAD)

Whitemare is a Russian Doom Community project, steeped in the theme of winter. Near the tail end of 2010, iddqd.ru had a speedmap competition; twelve levels produced from the event form the base of this megaWAD, some undergoing serious renovation. The other six were added in after the fact, forming the eighteen-map work released near the beginning of 2011. It's got a rudimentary framework-plot to boot. Demons can't abide by Christmas and New Years celebrations so it's Doomguy's job to stop them from ruining everyone's fun. And, yes, this WAD has a very slight Christmas theme in addition to the general winter feel, if the numerous Christmas trees made out of level geometry didn't tip you off.