Xmas / Holiday Lemmings 1991 - 1994 was a set of small Lemmings games based on Christmas. The landscapes are (generally) snowy and the lemmings are in Santa suits!
The first release was in 1991 as a gift to fans after the incredible success of both Lemmings and Oh No!. This was a freeware 4 level game which featured 2 unique Christmas levels and 2 levels from Oh No! More Lemmings. This game was released for the Amiga, Mac and PC.
The 1992 version was also a 4 level freeware game which featured 4 all new Christmas levels. I have found these levels slightly more difficult than the 1991 levels.
In 1993, Psygnosis made Christmas Lemmings a commercial release. This version contained 32 Christmas levels divided into 2 categories, Flurry and Blitz.
The 1994 was another commercial release containing 32 new Christmas levels plus the 32 from 1993. The Amiga version contained 2 player mode versions of each level. The categories in this game were Frost, Hail, Flurry (1993) and Blitz (1993).