Serious.sam.siberian.mayhem.merry.christmas.v1....

A "solid feature" of the (Patch 1.06) for Serious Sam: Siberian Mayhem is the permanent unlock for the Christmas Event via a new New Game+ perk . Key Christmas Features

: A unique cosmetic for the XPMR "Burner" Raygun, unlockable by finding a Christmas Tree and completing a special portal challenge on each of the game's five levels. Serious.Sam.Siberian.Mayhem.Merry.Christmas.v1....

If you were specifically looking for features from the update (which arrived earlier in August 2022), it added: Guide :: Christmas event: XPMR "Freezer" Raygun weapon skin A "solid feature" of the (Patch 1

: The update adds Christmas-themed game menus, holiday music by Anna Lazarev and Ivan Špeljak Jitz, and festive enemy variants, such as Sirian Werebulls with glowing red noses and bosses dressed as Santa Claus. and festive enemy variants